|DAQ|^2 = |PAQ| x |BCD| , ABCD #
Source: 2023 NZMO - New Zealand Maths Olympiad Round 1 p2
September 2, 2023
parallelogramareasarea of a trianglegeometry
Problem Statement
Let be a parallelogram, and let be a point on the side . Let the line through parallel to intersect the diagonal at point . Prove that where denotes the area of triangle .