Drawing and composing angles
Answers are for parents and teachers.
1
Explain how to draw an angle of 110° when the first ray points right. Say which scale to read.
Draw the ray, put the centre mark on its endpoint and the baseline on the ray, read the scale that starts at 0° on the right, mark 110°, take the protractor away and draw the second ray through the mark.
2
Angle PQR is 130°. A ray QS inside it makes angle PQS = 80°. Find angle SQR.
130° − 80° = 50°. Check: 80° + 50° = 130°.
3
On a straight line one of two angles is 75°. Find the other angle.
180° − 75° = 105°.
4
A windmill has 8 equal blades. What is the angle between neighbouring blades? What is the angle between two blades that have one blade between them?
360° ÷ 8 = 45°. With one blade between them the angle is 2 × 45° = 90°.
5
The hour hand goes from 3 o’clock to 6 o’clock. How many degrees does it turn? Is that a right angle?
3 hours × 30° = 90°. Yes, it is a right angle.