MathDB
2022 Geo Div 1 P4 (Div 2 P8)

Source:

February 28, 2022
geometry

Problem Statement

Let AA and BB be points on circle Γ\Gamma such that AB=10.AB=\sqrt{10}. Point CC is outside Γ\Gamma such that ABC\triangle ABC is equilateral. Let DD be a point on Γ\Gamma and suppose the line through CC and DD intersects ABAB and Γ\Gamma again at points EE and FD.F \neq D. It is given that points C,D,E,FC, D, E, F are collinear in that order and that CD=DE=EF.CD=DE=EF. What is the area of Γ?\Gamma?
Proposed by Kyle Lee