Geometry: Estimate Angles

In this activity, we will learn how to estimate the size of each angle.

e.g. Estimate the size of the angle.

Think of key angles such as: 30°, 60°, 90°, 120° and 180°.

A right angle is 90°, so 30° is a third of a right angle and 60° is two thirds of a right angle.

A straight line is 180°, so 120° is a right angle plus a third of a right angle.

Answer: The angle is about 120°.

Using a protractor, the exact size of this angle = 116°.