Practice!

Sample Problem

The following circles are divided into 4 equal parts each. In each circle, follow the turning arrow and write down the size of the angle it marks. Then write down the number of right angles represented by the turning arrow.

∠a = ° = right angles;

∠b = ° = right angles.

Solution

A circle is 360° and it is divided into 4 equal parts. So each part is 360° ÷ 4 = 90°.

1 right angle is 90°. So each part is 1 right angle.

(a)   ∠a = 90° × 2 = 180° = 2 right angles;

(b)  ∠b = 90° × 3 = 270° = 3 right angles;