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human
In triangle $VWX$ shown, $VX = \sqrt{13}$ and $VW = 3$. What is $\tan V$? [asy] pair V,W,X; W = (0,0); V = (0,3); X = (2,0); draw(V--W--X--V); draw(rightanglemark(V,W,X,7)); label("$W$",W,SW); label("$V$",V,NW); label("$X$",X,SE); label("$3$",(V+W)/2,NW); label("$\sqrt{13}$",(V+X)/2,NE); [/asy]
gpt
Because $\triangle VWX$ is a right triangle, $\tan V = \frac{WX}{VW}$. By the Pythagorean Theorem, $$WX = \sqrt{VX^2 - WX^2} = \sqrt{13 - 9} = \sqrt{4} = 2.$$Then $\tan V = \boxed{\frac{2}{3}}$.
human
An isosceles triangle has side lengths 8 cm, 8 cm and 10 cm. The longest side of a similar triangle is 25 cm. What is the perimeter of the larger triangle, in centimeters?
gpt
The ratio of the length of the longest sides of the small triangle to the large triangle is $10/25 = 2/5$, which must hold constant for all sides of the two triangles since they are similar. Thus the perimeters of the two triangles are also in the ratio of $2/5$. The small triangle has perimeter $8+8+10=26$, so the l...
human
Compute $\sin 315^\circ$.
gpt
Let $P$ be the point on the unit circle that is $315^\circ$ counterclockwise from $(1,0)$, and let $D$ be the foot of the altitude from $P$ to the $x$-axis, as shown below. [asy] pair A,C,P,O,D; draw((0,-1.2)--(0,1.2),p=black+1.2bp,Arrows(0.15cm)); draw((-1.2,0)--(1.2,0),p=black+1.2bp,Arrows(0.15cm)); A = (1,0); ...
human
Find $AX$ in the diagram. [asy] import markers; real t=.56; pair A=(0,0); pair B=(3,2); pair C=(.5,1.5); pair X=t*A+(1-t)*B; draw(C--A--B--C--X); label("$A$",A,SW); label("$B$",B,E); label("$C$",C,N); label("$X$",X,SE); markangle(n=1,radius=15,A,C,X,marker(markinterval(stickframe(n=1),true))); markangle(n...
gpt
The Angle Bisector Theorem tells us that \[\frac{AC}{AX}=\frac{BC}{BX}\]so \[AX=\frac{AC\cdot BX}{BC}=\frac{21\cdot24}{28}=\frac{7\cdot3\cdot6\cdot 4}{7\cdot4}=\boxed{18}.\]
human
In the diagram below, points $A$, $B$, $C$, and $P$ are situated so that $PA=2$, $PB=3$, $PC=4$, and $BC=5$. What is the maximum possible area of $\triangle ABC$? [asy] defaultpen(linewidth(0.8)); size(150); pair B = (0,0), C = (5,0), A = (2,3), P = (2.2,2); draw(A--B--C--cycle^^B--P^^C--P^^A--P); label("$A$",A,N); lab...
gpt
We first observe that by the Pythagorean theorem $\triangle PBC$ must be a right triangle with right angle at $P$, since $PB=3$, $PC=4$, and $BC=5$. $[\triangle PBC]=\frac{1}{2}(3)(4) = 6=\frac{1}{2}(PH)(5)$. Hence, the altitude $\overline{PH}$ from $P$ to $\overline{BC}$ has length $\frac{12}{5}$. Let $h$ be the leng...
human
A right triangle with legs $10$ and $8$ is similar to another right triangle with corresponding legs $x$ and $5$, respectively. What is the value of $x$? Express your answer as a decimal to the nearest hundredth.
gpt
By similarity, we know that $\frac{10}{x} = \frac{8}{5}$, so therefore $x = \frac{50}{8} = \boxed{6.25}$.
human
Pentagon ABCDE has a vertical line of symmetry. What is the $y$-coordinate of vertex C so that the area of the pentagon is 40 square units? [asy] unitsize(2mm); defaultpen(linewidth(.7pt)+fontsize(8pt)); dotfactor=4; pair A=(0,0), B=(0,4), C=(2,16), D=(4,4), E=(4,0); pair[] dots={A,B,C,D,E}; draw(B--C--D--E); dot(dot...
gpt
Write the area of pentagon $ABCDE$ as sum the areas of square $ABDE$ and triangle $BCD$. Since square $ABDE$ has area $4^2=16$ square units, triangle $BCD$ has area $40-16=24$ square units. If $h$ is the $y$-coordinate of point $C$, the height of triangle $BCD$ is $h-4$ units and its base is $4$ units. Solving $\fra...
human
Altitudes $\overline{AD}$ and $\overline{BE}$ of $\triangle ABC$ intersect at $H$. If $\angle BAC = 46^\circ$ and $\angle ABC = 71^\circ$, then what is $\angle AHB$? [asy] size(150); defaultpen(linewidth(0.8)); pair B = (0,0), C = (3,0), A = (1.8,2), P = foot(A,B,C), Q = foot(B,A,C),H = intersectionpoint(B--Q,A--P); ...
gpt
First, we build a diagram: [asy] size(150); defaultpen(linewidth(0.8)); pair B = (0,0), C = (3,0), A = (1.8,2), P = foot(A,B,C), Q = foot(B,A,C),H = intersectionpoint(B--Q,A--P); draw(A--B--C--cycle); draw(A--P^^B--Q); label("$A$",A,N); label("$B$",B,W); label("$C$",C,E); label("$D$",P,S); label("$E$",Q,E); label("$H$...
human
What is the total volume in cubic feet of three boxes if each box is a cube with edge length 4 feet?
gpt
Each box has volume $4^3=64$ cubic feet. Thus, three boxes have volume $64\cdot3=\boxed{192}$ cubic feet.
human
The endpoints of a diameter of circle $M$ are $(-1,-4)$ and $(-7,6)$. What are the coordinates of the center of circle $M$? Express your answer as an ordered pair.
gpt
The midpoint of a diameter of a circle is its center. Thus, $M$ is the midpoint of the segment from $(-1,-4)$ to $(-7,6),$ so $M$ has coordinates \[\left(\frac{-1+(-7)}{2},\frac{-4+6}{2} \right)=\boxed{(-4,1)}.\]
human
Compute $\sin 45^\circ$.
gpt
Let $P$ be the point on the unit circle that is $45^\circ$ counterclockwise from $(1,0)$, and let $D$ be the foot of the altitude from $P$ to the $x$-axis, as shown below. [asy] pair A,C,P,O,D; draw((0,-1.2)--(0,1.2),p=black+1.2bp,Arrows(0.15cm)); draw((-1.2,0)--(1.2,0),p=black+1.2bp,Arrows(0.15cm)); A = (1,0); O...
human
Compute $\cos 270^\circ$.
gpt
Rotating the point $(1,0)$ about the origin by $270^\circ$ counterclockwise gives us the point $(0,-1)$, so $\cos 270^\circ = \boxed{0}$.
human
The rectangle with vertices $(-1, y), (7, y), (-1, 3)$, and $(7, 3)$ has an area of 72 square units, and $y$ is positive. What is the value of $y$?
gpt
First we write the rectangle's side lengths in terms of the coordinates provided. The length is $7-(-1)=8$ and the height is $y-3.$ It follows that $8(y-3)=72,$ and $y=\boxed{12}.$ [asy] import graph; size(4cm); defaultpen(linewidth(0.7)+fontsize(10)); dotfactor=4; xaxis(Arrows(4)); yaxis(ymin=-2,Arrows(4)); pair A=(-1...
human
In rectangle $ABCD$, $P$ is a point on $BC$ so that $\angle APD=90^{\circ}$. $TS$ is perpendicular to $BC$ with $BP=PT$, as shown. $PD$ intersects $TS$ at $Q$. Point $R$ is on $CD$ such that $RA$ passes through $Q$. In $\triangle PQA$, $PA=20$, $AQ=25$ and $QP=15$. [asy] size(7cm);defaultpen(fontsize(9)); real sd = ...
gpt
Since $\angle ABP=90^{\circ}$, $\triangle ABP$ is a right-angled triangle. By the Pythagorean Theorem, $$BP^2=AP^2-AB^2=20^2-16^2=144$$ and so $BP=12$, since $BP>0$. Since $\angle QTP=90^{\circ}$, $\triangle QTP$ is a right-angled triangle with $PT=12$. Since $PT=BP=12$, then by the Pythagorean Theorem, $$QT^2=QP^2-PT...
human
The isosceles trapezoid shown has side lengths as labeled. How long is segment AC? [asy] unitsize(1.5mm); defaultpen(linewidth(.7pt)+fontsize(10pt)); dotfactor=3; pair A=(0,0), B=(21,0), C=(15,8), D=(6,8); pair[] dots={A,B,C,D}; draw(A--B--C--D--cycle); dot(dots); label("A",A,SW); label("B",B,SE); label("C",C,NE); la...
gpt
Define $E$ and $F$ to be the feet of the perpendiculars drawn to $AB$ from $C$ and $D$ respectively. Since $EF=CD=9$, we find $AF=(21-9)/2=6$ and $AE=AF+FE=15$. Also, from the Pythagorean theorem, $CE=DF=\sqrt{10^2-6^2}=8$. Again using the Pythagorean theorem, $AC=\sqrt{CE^2+AE^2}=\sqrt{8^2+15^2}=\boxed{17}$ units. ...
human
What is the smallest possible perimeter, in units, of a triangle whose side-length measures are consecutive integer values?
gpt
The smallest such triangle has lengths 1, 2, and 3. However, this triangle doesn't work since the sum of any two side lengths must be greater than the third side length (by the Triangle Inequality). The next smallest triangle has lengths 2, 3, and 4, which works. Thus, the smallest possible perimeter is $2+3+4=\boxed{9...
human
Either increasing the radius or the height of a cylinder by six inches will result in the same volume. The original height of the cylinder is two inches. What is the original radius in inches?
gpt
Let the original radius be $r$. The volume of the cylinder with the increased radius is $\pi \cdot (r+6)^2 \cdot 2$. The volume of the cylinder with the increased height is $\pi \cdot r^2 \cdot 8$. Since we are told these two volumes are the same, we have the equation $\pi \cdot (r+6)^2 \cdot 2 = \pi \cdot r^2 \cdot 8$...
human
Two sectors of a circle of radius $12$ overlap as shown, with $P$ and $R$ as the centers of the respective circles. Determine the area of the shaded region. [asy] draw((0,0)--(10.3923,-6)--(20.7846,0)--(10.3923,6)--cycle,black+linewidth(1)); filldraw((10.3923,6)..(12,0)..(10.3923,-6)--cycle,gray,black+linewidth(1)); f...
gpt
By symmetry, the areas of the two parts of the shaded region are equal. Consider the right part of the shaded region and the left triangle. [asy] draw((0,0)--(10.3923,-6)--(10.3923,6)--cycle,black+linewidth(1)); filldraw((10.3923,6)..(12,0)..(10.3923,-6)--cycle,gray,black+linewidth(1)); draw((0,0)--(10.3923,0),black+l...
human
The sides of triangle $PQR$ are tangent to a circle with center $C$ as shown. Given that $\angle PQR = 65^\circ$ and $\angle QRC = 30^\circ$, find $\angle QPR$, in degrees. [asy] unitsize(1.0 cm); pair Q, P, R, C; Q = (2.43,3.46); P = (0,0); R = (4.43,0); C = incenter(Q,P,R); draw(Q--P--R--cycle); draw(incircle(Q,P...
gpt
The circle with center $C$ is the incircle of $\triangle PQR$. So, any segment from a vertex of the triangle to $C$ is an angle bisector. From $\angle QRC = 30^\circ$, we find that $\angle QRP = 60^\circ$ because $RC$ is an angle bisector. The sum of the measures of the internal angles of a triangle is $180^\circ$, s...
human
The figure shows two concentric circles. If the length of chord AB is 80 units and chord AB is tangent to the smaller circle, what is the area of the shaded region? Express your answer in terms of $\pi$. [asy] defaultpen(linewidth(.8pt)); dotfactor=4; filldraw(circle((0,0),50),gray); filldraw(circle((0,0),30),white); ...
gpt
Call the point of tangency between the two circles $P$ and the center $O$. [asy] defaultpen(linewidth(.8pt)); dotfactor=4; filldraw(circle((0,0),50),gray); filldraw(circle((0,0),30),white); draw((-40,30)--(40,30)); draw((0,30)--(0,0)--(-40,30)); label("$P$",(0,30),N); label("$O$",(0,0),S); label("$A$",(-40,30),W); l...
human
$\Delta ABC$ is isosceles with $AC = BC$. If $m\angle C = 40^{\circ}$, what is the number of degrees in $m\angle CBD$? [asy] pair A,B,C,D,E; C = dir(65); B = C + dir(-65); D = (1.5,0); E = (2,0); draw(B--C--A--E); dot(D); label("$A$",A,S); label("$B$",B,S); label("$D$",D,S); label("$C$",C,N); [/asy]
gpt
Let $x$ be the number of degrees in $\angle ABC$. Since $\triangle ABC$ is isosceles with $AC=BC$, we have $\angle BAC=\angle ABC$. So, the three interior angles of $\triangle ABC$ measure $x^\circ$, $x^\circ$, and $40^\circ$. The sum of the angles in a triangle is $180^\circ$, so we have $$x+x+40 = 180,$$which we can...
human
Find the number of units in the length of diagonal $DA$ of the regular hexagon shown. Express your answer in simplest radical form. [asy] size(120); draw((1,0)--(3,0)--(4,1.732)--(3,3.464)--(1,3.464)--(0,1.732)--cycle); draw((1,0)--(1,3.464)); label("10",(3.5,2.598),NE); label("$A$",(1,0),SW); label("$D$",(1,3.464),NW)...
gpt
Label point $X$ as shown below, and let $Y$ be the foot of the perpendicular from $X$ to $AD$. [asy] size(120); pair A,B,C,D,E,F; A = dir(0); B = dir(60); C = dir(120); D = dir(180); E = dir(240); F = dir(300); label("$10$",(A+B)/2,NE); pair H=(E+C)/2; draw(D--H); draw(E--C); label("$D$",C,NW);label("$X$",D,W);label("...
human
The shaded region consists of 16 congruent squares. If $PQ = 6$ cm, what is the area of the entire shaded region? [asy] for(int i = 0; i < 5; ++i) { for(int j = 0; j < 2; ++j) { filldraw((i,j)--(i+1,j)--(i+1,j+1)--(i,j+1)--(i,j)--cycle,gray,linewidth(2)); } } for(int i = 0; i < 2; ++i) { for(int j = 0; j < 5; ++...
gpt
Imagine the square whose diagonal would be PQ. Clearly, that square would be formed of 9 of the shaded squares. The formula for the area of a square from its diagonal is $A = \frac{d^2}{2}$, therefore, the area of that imaginary square is 18. Thus, each smaller shaded square has area 2, making for a total of $\boxed...
human
A quadrilateral in the plane has vertices $(1, 3)$, $(1, 1)$, $(2, 1)$ and $(2006, 2007)$. How many square units is the area of the quadrilateral?
gpt
The quadrilateral is shown below: [asy] size(100); defaultpen(linewidth(.8)); draw((1,1)--(2,1)--(10,10.1)--(1,3)--cycle); draw((1,1)--(10,10.1),dashed); label("$A$", (1,1), S); label("$B$", (2,1), E); label("$C$", (10,10.1), N); label("$D$", (1,3), W); [/asy] Divide the quadrilateral into two triangles with the dashed...
human
Let $ABC$ be a triangle with $\angle BAC = 90^\circ$. A circle is tangent to the sides $AB$ and $AC$ at $X$ and $Y$ respectively, such that the points on the circle diametrically opposite $X$ and $Y$ both lie on the side $BC$. Given that $AB = 6$, find the area of the portion of the circle that lies outside the tria...
gpt
Let $O$ be the center of the circle, and $r$ its radius, and let $X'$ and $Y'$ be the points diametrically opposite $X$ and $Y$, respectively. We have $OX' = OY' = r$, and $\angle X'OY' = 90^\circ$. Since triangles $X'OY'$ and $BAC$ are similar, we see that $AB = AC$. Let $X''$ be the foot of the altitude from $Y'$ to ...
human
A sphere is inscribed in a cube. What is the ratio of the volume of the inscribed sphere to the volume of the cube? Express your answer as a common fraction in terms of $\pi$.
gpt
[asy] size(60); draw(Circle((6,6),4.5)); draw((10.5,6)..(6,6.9)..(1.5,6),linetype("2 4")); draw((10.5,6)..(6,5.1)..(1.5,6)); draw((0,0)--(9,0)--(9,9)--(0,9)--cycle); draw((0,9)--(3,12)--(12,12)--(9,9)); draw((12,12)--(12,3)--(9,0)); draw((0,0)--(3,3)--(12,3),dashed); draw((3,3)--(3,12),dashed); [/asy] Let the side len...
human
The angles of quadrilateral $ABCD$ satisfy $\angle A = 2\angle B = 3\angle C = 4\angle D$. What is the degree measure of $\angle A$, rounded to the nearest whole number?
gpt
Let $x$ be the degree measure of $\angle A$. Then the degree measures of angles $B$, $C$, and $D$ are $x/2$, $x/3$, and $x/4$, respectively. The degree measures of the four angles have a sum of 360, so \[ 360 = x+\frac{x}{2}+\frac{x}{3}+\frac{x}{4} = \frac{25x}{12}. \]Thus $x=(12\cdot 360)/25 = 172.8\approx \boxed{1...
human
A frustum of a right circular cone is formed by cutting a small cone off of the top of a larger cone. If a particular frustum has a lower base radius of 6 inches, an upper base radius of 3 inches, and a height of 4 inches, what is its lateral surface area? (The lateral surface area of a cone or frustum is the curved s...
gpt
We start by drawing the frustum. Let the top and bottom circles have centers $O_1$ and $O_2$ respectively, and label points $A$ and $B$ on the circumferences as shown such that $O_1$, $O_2$, $A$, and $B$ lie in the same plane. [asy] unitsize(0.5 cm); import geometry; defaultpen(linewidth(.8)+fontsize(10)); label("$O...
human
In regular pentagon $ABCDE$, diagonal $AC$ is drawn, as shown. Given that each interior angle of a regular pentagon measures 108 degrees, what is the measure of angle $CAB$? [asy] size(4cm,4cm); defaultpen(linewidth(1pt)+fontsize(10pt)); pair A,B,C,D,E; A = (0,0); B = dir(108); C = B+dir(39); D = C+dir(-39); E = (1,0...
gpt
Since $ABCDE$ is a regular pentagon, we know by symmetry that the measures of $\angle CAB$ and $\angle BCA$ are equal. We also know that the sum of the measures of the angles of $\triangle ABC$ equals $180$ degrees. Thus, if we let $x = $ the measure of $\angle CAB$ = the measure of $\angle BCA$, we have that $180 = 10...
human
The lengths of the three sides of a triangle are $7$, $x+4$ and $2x+1$. The perimeter of the triangle is 36. What is the length of the longest side of the triangle?
gpt
Since the perimeter of the triangle is 36, then $7+(x+4)+(2x+1)=36$ or $3x+12=36$ or $3x=24$ or $x=8$. Thus, the lengths of the three sides of the triangle are $7$, $8+4=12$ and $2(8)+1=17$, of which the longest is $\boxed{17}.$
human
In triangle $ABC$, $BC = 20 \sqrt{3}$ and $\angle C = 30^\circ$. Let the perpendicular bisector of $BC$ intersect $BC$ and $AC$ at $D$ and $E$, respectively. Find the length of $DE$.
gpt
We have that $D$ is the midpoint of $BC$, and that $CD = BC/2 = 20 \sqrt{3}/2 = 10 \sqrt{3}$. [asy] unitsize(3 cm); pair A, B, C, D, E; A = dir(133); B = dir(193); C = dir(-13); D = (B + C)/2; E = extension(A, C, D, D + rotate(90)*(B - C)); draw(A--B--C--cycle); draw(D--E); label("$A$", A, N); label("$B$", B, SW);...
human
What is the volume, in cubic units, of a cube whose surface area is 600 square units?
gpt
The surface area of a cube equals 6 times the area of each face (since there are 6 faces). If the cube has a sidelength of $s$, then the surface area equals $6s^2$. We set that equal to 600 and solve for $s$, which must be positive. $$600=6s^2\qquad\Rightarrow 100=s^2\qquad\Rightarrow 10=s$$ The volume of the cube is $...
human
In the diagram, the smaller circles touch the larger circle and touch each other at the center of the larger circle. The radius of the larger circle is $6.$ What is the area of the shaded region? [asy] size(100); import graph; filldraw(Circle((0,0),2),mediumgray); filldraw(Circle((-1,0),1),white); filldraw(Circle((1,0...
gpt
Label the center of the larger circle $O$ and the points of contact between the larger circle and the smaller circles $A$ and $B.$ Draw the radius $OA$ of the larger circle. [asy] size(120); import graph; filldraw(Circle((0,0),2),mediumgray); filldraw(Circle((-1,0),1),white); filldraw(Circle((1,0),1),white); draw((-2,...
human
The point $O$ is the center of the circle circumscribed about $\triangle ABC$, with $\angle BOC = 120^{\circ}$ and $\angle AOB = 140^{\circ}$, as shown. What is the degree measure of $\angle ABC$? [asy] pair A,B,C; draw(Circle((0,0),20),linewidth(0.7)); label("$O$",(0,0),S); A=(-16,-12); C=(16,-12); B=(3,19.7); draw(A...
gpt
Since $OA=OB=OC$, triangles $AOB$, $BOC$, and $COA$ are all isosceles. Hence \[ \angle ABC = \angle ABO + \angle OBC = \frac{180^{\circ}-140^{\circ}}{2}+ \frac{180^{\circ}-120^{\circ}}{2}=\boxed{50^{\circ}}. \]OR Since \[ \angle AOC = 360^{\circ}-140^{\circ}-120^{\circ}=100^{\circ}, \]the Central Angle Theorem implie...
human
In the diagram, $AOB$ is a sector of a circle with $\angle AOB=60^\circ.$ $OY$ is drawn perpendicular to $AB$ and intersects $AB$ at $X.$ What is the length of $XY ?$ [asy] draw((0,0)--(12,0),black+linewidth(1)); draw((0,0)--(10.3923,-6)..(12,0)..(10.3923,6)--(0,0),black+linewidth(1)); draw((10.3923,-6)--(10.3923,6),b...
gpt
Since $OY$ is a radius of the circle with centre $O,$ we have $OY=12.$ To find the length of $XY,$ we must find the length of $OX.$ Since $OA=OB,$ we know that $\triangle OAB$ is isosceles. Since $\angle AOB = 60^\circ,$ we have $$\angle OAB=\frac{1}{2}(180^\circ-60^\circ)=60^\circ.$$ Therefore, $$ \angle AOX = 180^\...
human
In triangle $ABC$, medians $AD$ and $CE$ intersect at $P$, $PE=1.5$, $PD=2$, and $DE=2.5$. What is the area of $AEDC$?
gpt
Note that $1.5^2 + 2^2 = 2.5^2,$ so $\triangle PED$ has a right angle at $P.$ (Alternatively, you could note that $(1.5, 2, 2.5)$ is half of the Pythagorean triple $(3,4,5).$) [asy]size(6cm);pair P=(0,0),D=(0,-2),E=(-1.5,0),C=(3,0),A=(0,4),B=extension(A,E,D,C);draw(A--B--C--cycle^^C--E^^A--D);draw(rightanglemark(E,P,D)...
human
In the diagram, $PQ$ and $RS$ are diameters of a circle with radius 4. If $PQ$ and $RS$ are perpendicular, what is the area of the shaded region? [asy] size(120); import graph; fill((-1,-1)--(-1,1)--(1,1)--(1,-1)--cycle,mediumgray); fill(Arc((0,0),sqrt(2),45,135)--cycle,mediumgray);fill(Arc((0,0),sqrt(2),225,315)--cy...
gpt
Diameters $PQ$ and $RS$ cross at the center of the circle, which we call $O$. The area of the shaded region is the sum of the areas of $\triangle POS$ and $\triangle ROQ$ plus the sum of the areas of sectors $POR$ and $SOQ$. Each of $\triangle POS$ and $\triangle ROQ$ is right-angled and has its two perpendicular sid...
human
We have a triangle $\triangle ABC$ such that $AB = AC = 8$ and $BC = 10.$ What is the length of the median $AM$?
gpt
Let's draw a sketch first. Since $\triangle ABC$ is isosceles, we know that $AM$ must form a right angle with $BC.$ [asy] pair A, B, C, M; A = (0, 6.24); B = (-5, 0); C = (5, 0); M = 0.5 * B + 0.5 * C; draw(A--B--C--cycle); draw(A--M); label("$A$", A, N); label("$B$", B, SW); label("$C$", C, SE); label("$M$", M, S); dr...
human
The radius of a cylinder is doubled and its height is tripled. If its original volume was 10 cubic feet, what is its volume now, in cubic feet?
gpt
Let the cylinder's original radius and height be $r$ and $h$, respectively. The new cylinder has volume \[ \pi (2r)^2(3h)=12\pi r^2 h, \] which is 12 times larger than the original volume. Since the original volume was 10 cubic feet, the new volume is $\boxed{120}$ cubic feet.
human
Find the ratio of the volume of the cone to the volume of the cylinder. Express your answer as a common fraction. [asy] import solids; size(150); import three; defaultpen(linewidth(0.8)); currentprojection = orthographic(5,0,3); revolution c = cylinder((0,0,0), 1, 3); revolution c2 = cone((0,0,0), 1,1.5); draw(c,black...
gpt
The volume of a cone with radius $r$ and height $h$ is $(1/3) \pi r^2 h$; the volume of a cylinder with similar dimensions is $\pi r^2 h$. The cone has the same radius as the cylinder and half the height, so it has $1/3$ the volume of half the cylinder and thus has $1/2\cdot 1/3 = 1/6$ the volume of the whole cylinder...
human
Suppose that we are given 40 points equally spaced around the perimeter of a square, so that four of them are located at the vertices and the remaining points divide each side into ten congruent segments. If $P$, $Q$, and $R$ are chosen to be any three of these points which are not collinear, then how many different p...
gpt
Without loss of generality, assume that our square has vertices at $(0,0)$, $(10,0)$, $(10,10)$, and $(0,10)$ in the coordinate plane, so that the 40 equally spaced points are exactly those points along the perimeter of this square with integral coordinates. We first note that if $P$, $Q$, and $R$ are three of these p...
human
An $\textit{annulus}$ is the region between two concentric circles. The concentric circles in the figure have radii $b$ and $c$, with $b>c$. Let $\overline{OX}$ be a radius of the larger circle, let $\overline{XZ}$ be tangent to the smaller circle at $Z$, and let $\overline{OY}$ be the radius of the larger circle that ...
gpt
The area of the annulus is the difference between the areas of the two circles, which is $\pi b^2 -\pi c^2$. Because the tangent $\overline{XZ}$ is perpendicular to the radius $\overline{OZ}$, $b^2 - c^2 = a^2$, so the area is $\boxed{\pi a^2}$.
human
The square with vertices $(-a, -a), (a, -a), (-a, a), (a, a)$ is cut by the line $y = x/2$ into congruent quadrilaterals. The perimeter of one of these congruent quadrilaterals divided by $a$ equals what? Express your answer in simplified radical form.
gpt
The line $y=\frac x2$ will intersect the two vertical sides of the square, as shown below: [asy] real f(real x) { return x/2; } import graph; size(6cm); real a = 8; pair A=(-a,a), B=(a,a), C=(a,-a), D=(-a,-a); draw(A--B--C--D--cycle); draw(graph(f,-11,11),Arrows); axes(Arrows(4)); dot("$(-a,a)$",A,N); dot("$(a,a)$",B...
human
When plotted in the standard rectangular coordinate system, trapezoid $ABCD$ has vertices $A(1, -2)$, $B(1, 1)$, $C(5, 7)$ and $D(5, 1)$. What is the area of trapezoid $ABCD$?
gpt
The two bases of the trapezoids are the segments $AB$ and $CD$, and the height is the perpendicular distance between the bases, which in this case is the difference of the $x$-coordinates: $5 - 1 = 4$. Similarly, the lengths of the bases are the differences of the $y$-coordinates of their two endpoints. Using the formu...
human
Polygon $ABCDEF$ is a regular hexagon. What is the measure in degrees of angle $ABF$?
gpt
In triangle $ABF$, the two acute angles are equal since $AB=AF$. Also, the measure of $\angle A$ is $180^\circ(6-2)/6=120^\circ$. Letting $x$ be the measure of $\angle ABF$, we have \[ 120^\circ+x+x=180^\circ \implies x=\boxed{30}\text{ degrees}. \] [asy] size(5cm); defaultpen(linewidth(0.7)); int i; pair A=dir(0), B=...
human
In right triangle $JKL$, angle $J$ measures 60 degrees and angle $K$ measures 30 degrees. When drawn, the angle bisectors of angles $J$ and $K$ intersect at a point $M$. What is the measure of obtuse angle $JMK$? [asy] import geometry; import olympiad; unitsize(0.8inch); dotfactor = 3; defaultpen(linewidth(1pt)+fontsi...
gpt
Since $JM$ bisects $\angle J$, we know that the measure of $\angle KJM$ is $60/2 = 30$ degrees. Similarly, since $MK$ bisects $\angle K$, we know that the measure of $\angle JKM$ is $30/2 = 15$ degrees. Finally, since the sum of the measures of the angles of a triangle always equals $180$ degrees, we know that the sum ...
human
Segment $s_1$ has endpoints at $(4,1)$ and $(-8,5)$. Segment $s_2$ is obtained by translating $s_1$ by $2$ units to the right and $3$ units up. Find the midpoint of segment $s_2$. Express your answer as $(a,b)$ with $a$ and $b$ integers.
gpt
The midpoint of segment $s_1$ can be found using the midpoint formula: $\left(\frac{4-8}2,\frac{1+5}2\right)=(-2,3).$ The midpoint of $s_2$ is the translation of the midpoint of $s_1$ be $2$ units to the right and $3$ units up. Thus its coordinates are $(-2+2,3+3)=\boxed{(0,6)}.$
human
Circle $T$ has a circumference of $12\pi$ inches, and segment $XY$ is a diameter. If the measure of angle $TXZ$ is $60^{\circ}$, what is the length, in inches, of segment $XZ$? [asy] size(150); draw(Circle((0,0),13),linewidth(1)); draw((-12,-5)--(-5,-12)--(12,5)--cycle,linewidth(1)); dot((0,0)); label("T",(0,0),N); l...
gpt
We can begin by using the circumference to solve for the radius of the circle. If the circumference is $12\pi$, then $2\pi r=12\pi$ which implies $r=6$. Now, we can draw in the radius $TZ$ as shown: [asy] size(150); draw(Circle((0,0),13),linewidth(1)); draw((-12,-5)--(-5,-12)--(12,5)--cycle,linewidth(1)); draw((0,0)-...
human
The lengths of two sides of a triangle are 33 units and 42 units. The third side also has an integral length. What is the least possible number of units in the perimeter of the triangle?
gpt
The sum of the smaller two sides must exceed the greatest side, so if $x$ is the missing side then $x+33>42\implies x>9$. The smallest integer greater than 9 is 10, so the least perimeter is $10+33+42=\boxed{85}$ units.
human
A cube has eight vertices (corners) and twelve edges. A segment, such as $x$, which joins two vertices not joined by an edge is called a diagonal. Segment $y$ is also a diagonal. How many diagonals does a cube have? [asy] /* AMC8 1998 #17 Problem */ pair A=(0,48), B=(0,0), C=(48,0), D=(48,48); pair E=(24,72), F=(24,24)...
gpt
There are two diagonals, such as $x$, in each of the six faces for a total of twelve face diagonals. There are also four space diagonals, such as $y$, which are within the cube. This makes a total of $\boxed{16}$.