It should be noted that the protractor is divided into the outer circle and the inner circle. When the zero scale line is in the inner circle, the degree of the inner circle should be read. When the outer circle, the degree of the outer circle can be read. The protractor can not only measure the angle, but also draw any angle. Straight lines, parallel lines, straight lines and parallel lines are not mentioned. The ruler can also be completed. Let's talk about how to use the protractor to draw an angle of a specified angle, This is a function that the ruler does not have (except for special angles).

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.