MathDB
Conic Section + Inscribed Sphere

Source:

March 23, 2008
conicsgeometry3D geometrysphereellipseratiogeometric series

Problem Statement

Suppose we have an (infinite) cone C \mathcal C with apex A A and a plane π \pi. The intersection of π \pi and C \mathcal C is an ellipse E \mathcal E with major axis BC BC, such that B B is closer to A A than C C, and BC \equal{} 4, AC \equal{} 5, AB \equal{} 3. Suppose we inscribe a sphere in each part of C \mathcal C cut up by E \mathcal E with both spheres tangent to E \mathcal E. What is the ratio of the radii of the spheres (smaller to larger)?