Problem #PRU-56555

Problems Geometry Plane geometry Circles Inscribed angle An angle between two chords or two secants

Problem

On a circle, the points \(A, B, C, D\) are given in the indicated order. \(M\) is the midpoint of the arc \(AB\). We denote the intersection points of the chords \(MC\) and \(MD\) with the chord \(AB\) by \(E\) and \(K\). Prove that \(KECD\) is an inscribed quadrilateral.