Topics
12. Geometry
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AustraliaNSW
Stage 3

12.07 Name and classify angles

Lesson
Practice
Lesson

Are you ready?

Being able to  compare angles  can help us in this lesson. Let's try this problem to review.

Examples

Example 1

Which of these angles is larger?

A
A right angle.
B
An obtuse angle.
Worked Solution
Create a strategy

Choose the option with a larger turn between the lines.

Apply the idea

The answer is option B.

Idea summary

Angles can be compared by how large the turn is between the lines.

Right angles

This video looks at right angles as quarter turns measuring 90\degree.

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Examples

Example 2

Which of the following is a right angle?

A
A right angle
B
An acute angle.
Worked Solution
Create a strategy

Look for the angle with a small square in the corner.

Apply the idea

Option A has a small square at the corner, so the answer is option A.

Idea summary

A right angle is exactly 90\degree. It can also be called a quarter turn.

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