Protractor:

Protractor usually made of transparent plastic is semi-circular or circular in shape. The circumference is graduated to 10 divisions and is numbered at each 100 interval. The line joining 00 to 1800 is identified the base line. The mid-point of the base line is identified the centre of the protractor. It is utilized for measuring or drawing angles other than those possible along with a set-square. It can be utilized also for dividing any given angle.

Figure: Protractor