Answer:
Nine is thirty-six percent of twenty-five
1) If we let the lengths of the legs be x and 2x, then by the Pythagorean theorem,

This means that the length of the hypotenuse is:

2) (Diagram attached) We know that
(in cm)
3) From the Pythagorean identity,

4) 
Just think of 8x10 it equals 80