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°.