Let Γ be a circle, and let ABCD be a square lying inside the circle Γ. Let Ca be a circle tangent interiorly to Γ, and also tangent to the sides AB and AD of the square, and also lying inside the opposite angle of ∠BAD. Let A′ be the tangency point of the two circles. Define similarly the circles Cb, Cc, Cd and the points B′,C′,D′ respectively. Prove that the lines AA′, BB′, CC′ and DD′ are concurrent.
Attachments:
