11

Part of 1970 IMO Longlists

Problems(1)

Connect Midpoints of Sides of Squares to Get Another Square

Source: ILL 1970 - Problem 11.

ABCD

A'B'C'D'

be two arbitrary squares in the plane that are oriented in the same direction. Prove that the quadrilateral formed by the midpoints of

AA',BB',CC',DD'

geometryvectorparallelogram