The shape of protractor is:
Semicircle
The protractor: It is a semi-circular device divided into 180 equal divisions, each division represents one unit measure of an angle, called a degree. The measure starts from 0° on the right-hand side and ends at 180° on the left-hand side and vice-versa. It is used to draw and measure angles.
Hence, the shape of the protractor is a semicircle.