First of all, we need to draw the vertex and side of the angle, which coincides with the time of measuring the angle. The vertex and side can be drawn at will, and their position does not affect the degree of the final angle. After completion, we need to make the vertex of the angle coincide with the center of the protractor, and the side coincides with the zero scale line.

As the name implies, it is an instrument used to measure the degree of angle, which can measure angle, inclination, verticality and levelness. In addition, the protractor is also a drawing tool, which can draw angles, vertical lines and parallel lines. It can be used as an internal and external right-angle ruler to open and close. It can also be used as a long and short ruler to read accurately and intuitively, and draw a circular dimension of the specified size. The protractor is usually made of plastic or iron and is often used with a compass.