1. The problem is to calculate the length of the right side of a right triangle. 2. We use the Pythagorean theorem which states that in a right triangle, the square of the hypotenuse ($c$) is equal to the sum of the squares of the other two sides ($a$ and $b$): $$c^2 = a^2 + b^2$$ 3. If the right side is one of the legs, say $b$, and we know the hypotenuse $c$ and the other leg $a$, we rearrange the formula to solve for $b$: $$b^2 = c^2 - a^2$$ 4. Taking the square root of both sides gives: $$b = \sqrt{c^2 - a^2}$$ 5. Substitute the known values of $c$ and $a$ into the formula and calculate $b$. 6. Remember, the length must be positive, so take the positive root.