On a miter saw, when you're cutting a 90 degree cut, the miter saw reads zero. On a protractor, it reads 90. So it's an unending source of confusion for people. RON HAZELTON: So Mark, show me how it works.
A ruler is used to measure units of length, inches, feet and yards. Standard rulers have inches on one side and centimeters on the other. A typical ruler measures up to 12 inches, and is equivalent to 30.48 centimeters. This is also equivalent to 1 foot. Each inch on a ruler has markings in between that are a fraction of an inch.
Measure four units along the other side. Using the same unit, measure along the second side, at â hopefully â a 90Âº angle to the first. Mark this point at four units. 4. Measure the distance between your marks. If the distance is 5 units, your corner is square. If the distance is less than 5 units, your corner is less than 90Âº. Move the sides apart.