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.

Drawing tools are usually made of plastic or iron. You can draw the desired angle according to your needs. Often used with compasses. It can draw angles, measure angles, draw vertical lines, parallel lines, measure inclinations, perpendicularity and levelness. It can be opened and closed as an internal and external right angle ruler. It can also be accurately and intuitively read as a long and short ruler, and draw a circular dimension of the specified size.