What formula is used to square a corner with a steel tape?

The formula used to square a corner with a steel tape is based on the Pythagorean theorem, which states that in a right triangle, the sum of the squares of the lengths of the two shorter sides equals the square of the length of the longest side (the hypotenuse). The 3-4-5 triangle is a classic example used in construction and masonry for this purpose, as it provides a simple way to achieve a right angle on the job site.

By measuring 3 units along one side, 4 units along another, and ensuring the distance between these two points is 5 units, you can effectively create a right angle (90 degrees) between the two sides. This method is practical and easy to remember, making it a staple in masonry and other construction trades.

The other options represent different sets of measures that can also create right angles or be used in various mathematical applications, but the 3-4-5 triangle is the most recognized and commonly utilized formula specifically for squaring corners in masonry work.