Use the 3-4-5 Rule to Line up the Perfect Angle
For construction purposes, instead of using a square tool to create a square corner, use a tape measure and some geometry to get a perfectly square corner every time.
In a classic example where classroom math meets real-world applications, Pythagoras’s Theorem can be used to build a barn or any structure that requires precise angles. The Pythagorean theorem states that the square of the hypotenuse (the side opposite to the right angle) is equal to the sum of the squares of the other two sides. This is displayed as A squared + B squared = C squared and is generally known as 3-4-5 in construction.
As shown in the video above, use a tape measure to measure and mark one board at 3 feet and another at 4 feet, then place the board right across both marks. The third board should be 5 feet in size and give a square corner. Works every time.
Construction Tool Tricks | Ethan Ewing (YouTube)