The lengths of the legs of the triangle are 1 and 3, find the area of the square.
Area of square (without proof) = [ product of leg lengths / sum of leg lengths ] ^2 =
( [ 1 * 3 ] / [ 1 + 3 ] )^2 = ( 3 / 4)^2 = 9 /16
I can easily prove this if you want me to