Art of Problem Solving

2025 AIME I Problems/Problem 6: Difference between revisions

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==Problem==
==Problem==
An isosceles trapezoid has an inscribed circle tangent to each of its four sides. The radius of the circle is <math>3</math>, and the area of the trapezoid is <math>72</math>. Let the parallel sides of the trapezoid have lengths <math>r</math> and <math>s</math>, with <math>r \neq s</math>. Find <math>r^2+s^2</math>
An isosceles trapezoid has an inscribed circle tangent to each of its four sides. The radius of the circle is <math>3</math>, and the area of the trapezoid is <math>72</math>. Let the parallel sides of the trapezoid have lengths <math>r</math> and <math>s</math>, with <math>r \neq s</math>. Find <math>r^2+s^2</math>
==Diagram==
<asy>
unitsize(0.5 cm);
real r = 12 + 6*sqrt(3);
real s = 12 - 6*sqrt(3);
real h = 6; 
pair A = (-r/2, 0);
pair B = ( r/2, 0);
pair C = ( s/2, h);
pair D = (-s/2, h);
draw(A--B--C--D--cycle);
pair O = (0, h/2);
draw(circle(O, 3));
dot(A); label("$A$", A, SW);
dot(B); label("$B$", B, SE);
dot(C); label("$C$", C, NE);
dot(D); label("$D$", D, NW);
dot(O);
label("$O$", (0,h/2), E);
label("$r$", midpoint(A--B), S);
label("$s$", midpoint(C--D), N);
</asy>

Revision as of 17:06, 13 February 2025

Problem

An isosceles trapezoid has an inscribed circle tangent to each of its four sides. The radius of the circle is $3$, and the area of the trapezoid is $72$. Let the parallel sides of the trapezoid have lengths $r$ and $s$, with $r \neq s$. Find $r^2+s^2$

Diagram

[asy] unitsize(0.5 cm);  real r = 12 + 6*sqrt(3);  real s = 12 - 6*sqrt(3);  real h = 6;    pair A = (-r/2, 0); pair B = ( r/2, 0); pair C = ( s/2, h); pair D = (-s/2, h);  draw(A--B--C--D--cycle);  pair O = (0, h/2); draw(circle(O, 3));  dot(A); label("$A$", A, SW); dot(B); label("$B$", B, SE); dot(C); label("$C$", C, NE); dot(D); label("$D$", D, NW);  dot(O); label("$O$", (0,h/2), E);  label("$r$", midpoint(A--B), S); label("$s$", midpoint(C--D), N); [/asy]