# Try some yourself

## Question 1

Calculate all the angles at the centres of these objects.

### Answer

- (a) Each of the four angles is 360° ÷ 4 = 90°.

- (b) The two upper angles are both 180° ÷ 2 = 90°, and the lower angle is 180°.

- (c) Each of the six angles is 360° ÷ 6 = 60°.

- (d) Each of the twenty angles is 360° ÷ 20 = 18°.

- (e) The acute angle between the hands is 360° ÷ 12 = 30°; the reflex angle is 360° − 30° = 330°.

- (f) Each of the three angles is 360° ÷ 3 = 120°.

OpenLearn - Geometry
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