An angle is a measure of turn. It shows how far something has rotated. It is often displayed as the rotation between two line segments.

A point is an exact location. It has no size, only position.

A vertex is a point where two or more lines meet.

A scale is a number line with equal divisions for equal values.

Measure the size of angles accurately using a protractor

Maths

In this unit pupils will compare the size of angles where there is a clear visual difference and use the terms acute, obtuse and reflex when describing the size of angles or amount of rotation with relation to right angles using a unit called degrees. In the future unit pupils will use knowledge of shape properties to draw, sketch and identify shapes.

In the prior unit pupils completed and composed symmetrical shapes from two congruent shapes and investigate lines of symmetry in 2D shapes. In this unit pupils will compare the size of angles where there is a clear visual difference and use the terms acute, obtuse and reflex when describing the size of angles or amount of rotation with relation to right angles using a unit called degrees.

Angles: compare, name, estimate and measure angles

Which image shows the protractor placed correctly to measure the angle?

Read the protractor scale to measure the angle. {{ }}°

Guess the size of a based on the angle of 115°

Sofia measured the obtuse angle in order to find the missing angle a. What is her next step?

Jun measured the acute angle in order to find the missing angle a. Tick what his next steps could be.

A triangle with three equal sides and three equal vertices.

A triangle with two equal sides and two equal vertices.

A triangle with no equal sides or vertices.

Which of these is the best estimate for the angle shown?

The image is not to scale. What is the value of missing angle a? a = {{ }}°

The image is not to scale. Calculate missing angle a. a = {{ }}°

The image is not to scale. Complete the sentence. I estimate that the size of angle a is ___ degrees.

This lesson will soon be taken down.

Measure the size of angles accurately using a protractor

Lesson outcome