given a right triangle with hypotenuse of 12.5 cm, side y of 7.2 cm? find length of side x and size of other two angles? so you set it up as pythagoreum theory? 12.5= x^2 + 7.2

Pythagoras OK, but remember you have to square all the sides.

12.5^2= x^2 + 7.2^2
156.25 = x^2 + 51.84