Topics
11. Shapes and angles
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AustraliaNSW
Stage 2

11.02 Compare angles

Lesson
Practice
Lesson

Are you ready

Can you identify a half turn?

Examples

Example 1

Which of these clocks shows a half turn?

A
A clock where the long hand is at 12 and small hand is at 5
B
A clock where the long hand is at 12 and small hand is at 6
Worked Solution
Create a strategy

Choose the clock that is split into two equal parts by its hands.

Apply the idea

In option A, the space from 12 to 5 is smaller than the space from 5 and 12. So the clock is not split into two equal parts.

In option B, the space from 12 to 6, and from 6 to 12 are the same. So the clock is split into two equal parts.

So option B is the correct answer.

Idea summary

A turn is a rotation around a point. A half turn shows a rotation halfway around the clock.

Identify angles

Angles are a measure how much something turns and they are all around you. Let's learn about where we may see angles.

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Examples

Example 2

Which door has made a bigger angle when opened?

A
A red door open wide.
B
A red door slightly open.
Worked Solution
Create a strategy

Choose the door with a wider opening.

Apply the idea

In option A, we can see that the door is open wide and creates a big angle.

In option B,the door is opened only on a small amount which creates a small angle.

So option A is the correct answer.

Idea summary

An angle measures the amount of turning between two lines.

Compare angles

Let's look at how similar objects can have different angles. Let's look at how angles can be bigger, smaller or the same.

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Examples

Example 3

In the clocks shown, think of the angle from the minute hand to the hour hand going clockwise.

Which clock shows the bigger angle?

A
A clock where the minute hand is at 12 and the hour hand is at 5.
B
A clock where the minute hand is at 12 and the hour hand is at 2.
Worked Solution
Create a strategy

Compare and identify the bigger angle measure.

Apply the idea
2 clocks showing the angles between the minute and hour hands. Ask your teacher for more information.

The angle is the amount of turning that the hour hand has done away from the minute hand.

In option A the hour hand has turned a large angle away from the minute hand as shown.

In option B the hour hand has turned a small angle away from the minute hand as shown.

Option A is the correct answer.

Idea summary

Even if we make the arms of an angle longer, the size of the angle doesn't change.

Outcomes

MA2-16MG

identifies, describes, compares and classifies angles

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