MathDB
2017-2018 Spring OMO Problem 28

Source:

April 3, 2018

Problem Statement

In ABC\triangle ABC, the incircle ω\omega has center II and is tangent to CA\overline{CA} and AB\overline{AB} at EE and FF respectively. The circumcircle of BIC\triangle{BIC} meets ω\omega at PP and QQ. Lines AIAI and BCBC meet at DD, and the circumcircle of PDQ\triangle PDQ meets BC\overline{BC} again at XX. Suppose that EF=PQ=16EF = PQ = 16 and PX+QX=17PX + QX = 17. Then BC2BC^2 can be expressed as mn\frac mn, where mm and nn are relatively prime positive integers. Find 100m+n100m + n.
Proposed by Ankan Bhattacharya and Michael Ren