The Pythagorean Theorem can be used to find the length of the third side of a right triangle when given the measurements of the other two sides. It can also be used to determine if a triangle is acute, right, or obtuse. This is done by comparing the square of the longest side to the sum of the squares of the two shorter sides. This information is useful in design and planning, both personally and professionally, since right triangles can be created just about anywhere.