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<ABM=<MBP wanted, AB //PC , PM_|_BM , median (2021 Kyiv City MO 8.4)

Source:

February 16, 2021
geometryequal anglesangles

Problem Statement

Let BMBM be the median of the triangle ABCABC, in which AB>BCAB> BC. Point PP is chosen so that ABPCAB \parallel PC and PMBMPM \perp BM. Prove that ABM=MBP\angle ABM = \angle MBP.
(Mikhail Standenko)