If I tell you that you have a right triangle with one leg having length a and another

C is found using the Pythagorean theorem:

C = sqrt(a^2 + b^2)

In this case, where energy output is the same as energy input, the output can be described as 100% or the system can be described as being 100% efficient. when efficiency is 100%, there are no energy losses in the form of heat, light, etc and the amount of energy input is equal to the amount of energy output.