MathDB

Let

ABCD

and

A'B'C'D'

be two squares, both are oriented clockwise. In addition, it is assumed that all points are arranged as shown in the figure.Then it has to be shown that the sum of the areas of the quadrilaterals

ABB'A'

and

CDD'C'

equal to the sum of the areas of the quadrilaterals

BCC'B'

and

DAA'D'

. https://cdn.artofproblemsolving.com/attachments/0/2/6f7f793ded22fe05a7b0a912ef6c4e132f963e.png

Problem Statement