midpoints of sides are vertices of square.
Source: TOT 385 1993 Autumn A J3 - Tournament of Towns
June 12, 2024
geometrysquaremidpoints
Problem Statement
Three angles of a non-convex, non-self-intersecting quadrilateral are equal to degrees (i.e. the last equals degrees). Prove that the midpoints of its sides are vertices of a square.(V Proizvolov)