MathDB
triangles with equal areas

Source: SRMC 2023, P1

December 28, 2023
geometrytrapezoid

Problem Statement

Let ABCDABCD be a trapezoid with ADBCAD\parallel BC. A point MM is chosen inside the trapezoid, and a point NN is chosen inside the triangle BMCBMC such that AMCNAM\parallel CN, BMDNBM\parallel DN. Prove that triangles ABNABN and CDMCDM have equal areas.