When squaring the corner of a framed wall, some carpenters use this method to make sure the corner is at a 90 degree angle.

The 3-4-5 method ensures the corner of a wall frame will be at 90 degrees. A mark is made 3 feet from the corner on one wall, while another mark is made 4 feet from the corner on the other wall. The walls are then adjusted until the distance between the two marks is exactly 5 feet, creating a 3-4-5 triangle with a corner angle of 90 degrees.

Asked by Jason Forbes · Last updated 5 years ago · 97.5K views · SOURCE