MathDB
Cocentric Circles of radii 3,4,5

Source: 2012 AIME I Problem 13

March 16, 2012
geometrygeometric transformationreflectiontrigonometryrotationanalytic geometry3D geometry

Problem Statement

Three concentric circles have radii 33, 44, and 55. An equilateral triangle with one vertex on each circle has side length ss. The largest possible area of the triangle can be written as a+bcda+\frac{b}{c}\sqrt{d}, where a,b,ca,b,c and dd are positive integers, bb and cc are relatively prime, and dd is not divisible by the square of any prime. Find a+b+c+da+b+c+d.