What is the proper method to ensure a 90 degree angle during construction?

The 3-4-5 method is a well-known technique used to establish a right angle, or a 90-degree angle, effectively and accurately during construction. This method utilizes the Pythagorean theorem, which states that in a right triangle, the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the lengths of the other two sides.

In practice, this method involves measuring lengths of 3 units and 4 units from a point, then measuring the distance diagonally between these two points. If the distance matches 5 units, a perfect right angle is established. This technique is particularly useful in laying out foundations, framing walls, and aligning various elements of construction that require precision.

Other methods listed may sound similar or may even have practical uses, but they do not specifically achieve the reliable establishment of a right angle as effectively as the 3-4-5 method.