A protractor is a tool used to measure angles
A protractor is a transparent plastic tool designed to measure angles. They are usually semicircular but also are available in a full circle 360° version.
||The small hole near the bottom of the protractor is aligned over the
vertex of the angle to be measured.
||The line along the bottom of the protractor is aligned along one of the angle's legs.
Note: It is not the edge of the protractor body itself, but parallel to it.
||The angle of the other leg is read from one of the two scales, whichever is more convenient.
For an animated demonstration of using the protractor see Using a Protractor
Related angle topics
(C) 2009 Copyright Math Open Reference. All rights reserved