1. Geometry
Level 1

2. An acute angle is between 0 and 90 degrees
Angle names
Acute angle
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An acute angle is between 0 and 90 degrees

3. An obtuse angle is between 90 and 180 degrees
Angle names
Obtuse angle
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An obtuse angle is between 90 and 180 degrees

4. A reflex angle is between 180 and 360 degrees
Angle names
Reflex angle
A reflex angle is between 180 and 360 degrees

5. A right angle is 90 degrees
Angle names
Right angle
A right angle is 90 degrees

6. A right angle is 90 degrees
Angle names
Right angle
A right angle is 90 degrees

7. A straight line is 180 degrees
Angle names
Straight angle
A straight line is 180 degrees

8. Naming angles
The angle is at B A B C

9. Guessing the angle size
The clock is divided into 12 hours.
One complete circle is 360 degrees.
Each hour makes 30 degrees.

19. What angle do the hands of the clock make?
4 lots of 30 degrees.
120 degrees.
OR the reflex angle is 240 degrees.

20. Guess the angle size OR

21. Complementary angles
Two angles which add up to 90 degrees are said to be complementary.

22. Complementary angles
What is the complement of 58 degrees? ?

23. Complementary angles
32 degrees

24. Complementary angles
What is the complement of 45 degrees? ? ?

25. Complementary angles
45 degrees

26. Supplementary angles
Two angles which add up to 180 degrees are said to be supplementary.

27. Supplementary angles
What is the supplement of 120 degrees? ? ?

28. Supplementary angles
60 degrees? ?

29. Supplementary angles
What is the supplement of 40 degrees? ?

30. Supplementary angles
What is the supplement of 140 degrees?

31. Measuring angles
We use a protractor to measure angles.

32. There are two scales marked on your protractor

33. First decide if your angle is acute or obtuse
This angle is acute

34. Read the acute scale.

35. The angle is 56 degrees.

36. This angle is obtuse.

37. Read the obtuse scale.

38. The angle is 124 degrees.