Ty! Rectangles are 2-dimensional cuboids, a square is a special rectangle. The 2 sides a & b of a rectangle relate to its diagonal as follows: a²+b²=c² c=a+d a=d(m²-1)/2 b=dm c=d(m²+1)/2 d=2,m=6 35²+12²=(35+2)² d=4,m=3 16²+12²=(16+4)² d=6,m=2 9²+12²=15² d=8,m=3/2 5²+12²=13² I hope this is useful.