In this activity, we will practise spotting acute and obtuse angles.

Acute angles are less than 90° and are the smallest type of angle - (that's why they are 'a cute' type of angle!)

Obtuse angles are a bit bigger - more than 90°, but less than 180°.

Let's try an example question.

Example

Sort these angles into acute and obtuse.

(a) (b) (c)

(d) (e) (f)
 

Answer

Acute angles: c, d, e.  

These are less than 90° (a right angle).

Obtuse angles: a, b, f.  

These are more than 90° (a right angle) but less than 180° (a straight line).

Are you ready to have a go at sorting some angles out?