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.
How to Find the Measurement of the Diagonal Inside a Rectangle. Three Methods: Using the Length and the Width Using the Area and Perimeter Using the Area and Relational Side Lengths Community Q&A. A diagonal is a straight line that connects one corner of a rectangle to the opposite corner. A rectangle has two diagonals, and each is the same length. If you know side lengths of the rectangle, you can easily find the length of the diagonal using the Pythagorean Theorem, since a diagonal divides a rectangle into two right triangles.