This video in the Education category will show you how to use a protractor to measure an angle. This video is from Brightstorm. In Geometry it is important to know how to measure an angle. This is a very simple and easy process. In order to measure an angle, you will need a protractor. Every protractor has a base and a center point marked on the base. You will put the center point on the vertex of the angle. Then align the base line of the protractor perfectly on one side of the angle. Now check the reading over the other line of the angle. That is the value of the angle in degrees.