MathDB

253

Part of 1978 All Soviet Union Mathematical Olympiad

Problems(1)

ASU 253 All Soviet Union MO 1978 equal angles given and wanted, parallelogram

Source:

7/6/2019
Given a quadrangle ABCDABCD and a point MM inside it such that ABMDABMD is a parallelogram. ∠CBM=∠CDM \angle CBM = \angle CDM. Prove that the ∠ACD=∠BCM \angle ACD = \angle BCM.
geometryparallelogramequal angles