Free practice on Angles for Class 5, following the Cameroon primary school curriculum (English subsystem). Every answer is explained, so a parent who is not sure of the answer can still help.
Acute: less than 90°. Right: exactly 90°. Obtuse: between 90° and 180°. Straight: 180°. Reflex: more than 180°.
| Angle | Size |
|---|---|
| Acute | 0° to 89° |
| Right | exactly 90° |
| Obtuse | 91° to 179° |
| Straight | 180° |
| Reflex | 181° to 359° |
Place the middle mark on the vertex of the angle. Line up 0° with one arm. Read where the other arm crosses. Use the inner or outer scale — depending on which side the 0° starts.
The three angles of any triangle add up to 180°. So if two angles are 60° and 70°, the third is 180 − 130 = 50°. Isosceles triangle has TWO equal angles.
| Type | Special property |
|---|---|
| Equilateral | All sides equal, all angles 60° |
| Isosceles | 2 sides equal, 2 angles equal |
| Right | One angle = 90° |
| Scalene | All sides different |
How many degrees are in a right angle?
Write your answer, then check below.
Answer: 90
An angle of 45° is:
Answer: A. acute
Acute angles are less than 90°.
An angle of 120° is:
Answer: C. obtuse
Obtuse angles are between 90° and 180°.
Which instrument do we use to measure angles?
Answer: B. a protractor
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