1. The problem states the Pythagorean theorem: $A^2 + B^2 = C^2$. 2. This formula relates the lengths of the sides of a right triangle, where $A$ and $B$ are the legs and $C$ is the hypotenuse. 3. To find the length of one side, you can rearrange the formula. For example, to find $C$, use: $$C = \sqrt{A^2 + B^2}$$ 4. To find $A$ or $B$, rearrange as: $$A = \sqrt{C^2 - B^2} \quad \text{or} \quad B = \sqrt{C^2 - A^2}$$ 5. Remember, the hypotenuse $C$ is always the longest side. 6. This theorem only applies to right triangles. 7. Example: If $A=3$ and $B=4$, then $$C = \sqrt{3^2 + 4^2} = \sqrt{9 + 16} = \sqrt{25} = 5$$ 8. So the hypotenuse $C$ is 5 units long.