When working with 45-45-90 triangles the hypotenuse is the same as the other legs multiplied by root 2. Therefore if you need to find the legs and already have the hypotenuse, divide the hypotenuse by root 2.
10/ sqrt(2) = 7.1 is the rounded answer.
to double check your work just multiply 7.1 by the square root of 2 and you'll get <em>close</em> to 10. (because the answer is rounded and not exact.)
