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Girls in Math at Yale 2022 Problem 12: Computationalized Oly Geo part n

Source:

February 27, 2022
Yalecollege

Problem Statement

Let ABCABC be a triangle with AB=5AB = 5, BC=7BC = 7, and CA=8CA = 8, and let DD be a point on arc BC^\widehat{BC} of its circumcircle Ω\Omega. Suppose that the angle bisectors of ADB\angle ADB and ADC\angle ADC meet ABAB and ACAC at EE and FF, respectively, and that EFEF and BCBC meet at GG. Line GDGD meets Ω\Omega at TT. If the maximum possible value of AT2AT^2 can be expressed as ab\frac{a}{b} for positive integers a,ba, b with gcd(a,b)=1\gcd (a,b) = 1, find a+ba + b.
Proposed by Andrew Wu