Maths Library

Types of Angles: Year 3 maths

This topic covers classifying angles according to their size. The worksheet practises categorising angles as acute, right, obtuse, straight, or reflex from diagrams and degree measurements.

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What this covers

Types of Angles is taught in Year 3 (age 8 to 9) as a topic to introduce. It sits in the Geometry strand.

Worked example

Classify an angle measuring 135 degrees.

  1. Compare the angle to reference benchmarks: 90 degrees and 180 degrees
  2. Note that 135 is greater than 90 and less than 180
  3. An angle between 90 and 180 degrees is obtuse

Answer: Obtuse

Difficulty scale

The sheet generator offers five difficulty settings for this topic.

  1. Identifying right angles compared to sharp (acute) angles
  2. Classifying given degree values as acute, right, or obtuse
  3. Identifying acute, right, and obtuse angles from diagrams
  4. Classifying reflex and straight angles from diagrams and values
  5. Estimating angle sizes to the nearest 10 degrees before classifying

Common mistakes

  • Thinking the size of an angle depends on the length of its arms
  • Confusing obtuse and reflex angles

Curriculum links

Indicative matches to Australian Curriculum v9. Check wording and codes against the official document.

  • AC9M3SP02 Identify angles as measures of turn and compare angles to right angles.

Sample sheet and answers

Six questions at the level's usual difficulty. Open the editor to change, add or regenerate any of them.

Types of Angles

Year 3 maths

Qs
6
Marks
6
NameDateScore / 6
1.
Name the type of angle shown, and give its size.
[1]
2.
Name the type of angle shown, and give its size.
[1]
3.
Name the type of angle shown, and give its size.
[1]
4.
Name the type of angle shown, and give its size.
[1]
5.
Name the type of angle shown, and give its size.
[1]
6.
Name the type of angle shown, and give its size.
[1]

Answer key

  1. an acute angle, 45°An angle less than 90° is acute, 90° is a right angle and more than 90° is obtuse; The angle is 45°
  2. a right angle, 90°An angle less than 90° is acute, 90° is a right angle and more than 90° is obtuse; The angle is 90°
  3. an obtuse angle, 110°An angle less than 90° is acute, 90° is a right angle and more than 90° is obtuse; The angle is 110°
  4. an obtuse angle, 135°An angle less than 90° is acute, 90° is a right angle and more than 90° is obtuse; The angle is 135°
  5. an obtuse angle, 120°An angle less than 90° is acute, 90° is a right angle and more than 90° is obtuse; The angle is 120°
  6. a right angle, 90°An angle less than 90° is acute, 90° is a right angle and more than 90° is obtuse; The angle is 90°