I can't get this problem... no idea how to do it. Can't use coordinates / angles, just straightforward geometry. (by angles I mean, you cant use a calculator to find em, then do everything from there) Any help appreciated... thanks "A card 12cm long and 6 cm wide is cut along a diagonal to form two congruent triangles. The triangles are arranged as shown. Find the area of the region where the triangles overlap."