posted by shweta .
a diagonal of a rectangle is 10 cm long. what is its perimeter.
ok to find a diagonal you use the Pythagorean theorem which is a^2 + b^2 = c^2 ok? c^2 is the diagnol. So basically a^2 + b^2 = 100 ok? so what two squares equal 100. well 64+36=100 take the square root of those two which is 8 and 6. so the perimeter is 28 cm long