Simply put: the hypotenuse is the longest side of a right triangle (also called a right angled triangle). Professionals and DIYers use the hypotenuse constantly for squaring projects – everything from picture frames to concrete pads. You don’t need to compute the hypotenuse for each project you work on, which can be a real time consuming challenge. Simply remember this: if one leg is 3 and the other is 4 – the hypotenuse is always 5. It can be 3/4 inches, 3/4 feet, 3/4 yards or 3/4 millimeters. So, just measure and mark the 3 and the 4 and then adjust your project until you get a perfect 5 hypotenuse – it’s fast, accurate and easy! Read about how to calculate the hypotenuse.