What are right, acute, obtuse and reflex angles?

Children start learning the language of direction in Year 1, when they talk about quarter, half and full turns. Teachers encourage children to learn about turns by getting them to stand up and make quarter, half and full turns around the classroom. They may also give children a small figurine or doll for them to place on a picture and practise making various turns with. It is vital that children understand the concept of these turns, as it is the foundation for learning about angles.  

In Year 3, children will need to recognise right angles and to know that two right angles make a half turn, three make three-quarters of turn and four a complete turn. They need to identify whether angles are greater than or smaller than a right angle.

In Year 4, children need to know about acute and obtuse angles.

Teachers usually spend a significant amount of time teaching children how to use a protractor, as they often find this difficult.

Protractors are marked from 0˚ to 180˚ from left to right, but also from right to left, which can take some getting used to! Children are shown again that two right angles make up a straight line and since 90˚ x 2 = 180˚, this is the measurement for a straight line. 

When it comes to acute and obtuse angles, children may be given a set of angles to cut out, measure and then sort into two groups.  They may also be given questions similar to the following:

Which of these shapes has one obtuse angle and two acute angles?
(The answer is the third shape.)

Look at the inside angles of this shape.  Mark the acute angles in red, the obtuse angles in blue and the reflex angle in green.

To help your child put their knowledge of shapes and angles into practice download angles worksheets and other geometry worksheets.