Description
The protractor is a drawing instrument, used for measuring and drawing angles. Protractors began to appear in the sixteenth century, often in sets of drawing instruments which also included rulers, scales, dividers, squares and sectors, and were originally used with sea charts. Simple semicircular protractors work by showing how many degrees in an angle when one line of a shape is placed along the base line of the protractor with the point of the angle in the centre.