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P in circumcircle of an equilateral ABC, AP cuts BC at A', area of A'B'C'

Source: 2014 Oral Moscow Geometry Olympiad grades 10-11 p5

August 9, 2019
geometrycircumcirclearea of a triangleareaEquilateralEquilateral Triangle

Problem Statement

Given a regular triangle ABCABC, whose area is 11, and the point PP on its circumscribed circle. Lines AP,BP,CPAP, BP, CP intersect, respectively, lines BC,CA,ABBC, CA, AB at points A,B,CA', B', C'. Find the area of the triangle ABCA'B'C'.