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.
The red lines on these rulers are marked at 1/2, and 1. The next smallest marks on a ruler are 1/4ths. The red marks on these rulers are at 1/4, 1/2, 3/4, and 1. (1/2 is the same as 2/4) The next smallest marks on a ruler are 1/8ths. The red marks on these rulers are at 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, and 1. The next smallest mark, if there are any, are 1/16ths. The red marks on this ruler are at 1/16, 1/8, 3/16, 1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16, 7/8, 15/16, and 1.