AD=AB+CD, tangent circle to 3 sides, cyclic (2020 Novosibirsk Oral Geo Oly 9.7)
Source:
May 24, 2021
geometryCyclicTangents
Problem Statement
The quadrilateral is known to be inscribed in a circle, and that there is a circle with center on side tangent to the other three sides. Prove that .