Introduction of Different kinds of Angles in Grade 7

Different kinds of angles, naming an angle and angles pairs for grade 7 third quarter

1. ANGLES

2. WHAT ARE ANGLES? The space between two intersecting straight lines, at the point in which they meet. The point where they meet is called the vertex. Angles are measured in degrees. straight line straight line vertex degrees

3. straight line straight line vertex degrees

4. Acute (>0, <90 degrees) Right (90 degrees) Obtuse (>90, <180 degrees) Straight (180 degrees) Reflex (>180, <360 degrees) Revolution (360 degrees) smallest largest TYPES OF ANGLES

5. The internal measurement of two straight lines, where the angle measures more than 0 but less than 90. ACUTE ANGLES

6. A right angle is equal to 90 RIGHT ANGLES

7. The internal measurement of two straight lines, where the angle measures more than 90 but less than 180. OBTUSE ANGLES

8. A straight angle is equal to 180 STRAIGHT ANGLES

9. The external measurement of two straight lines, where the angle measures more than 180 but less than 360. REFLEX ANGLES

10. A full rotation of 360 REVOLUTION ANGLES

11. A right angle A An acute angle B An obtuse angle C Which Angle Is This?

12. An acute angle B

13. An acute angle A A reflex angle B A right angle C Which Angle Is This?

14. A right angle C

15. An acute angle A An obtuse angle B A right angle C Which Angle Is This?

16. An acute angle A

17. A straight angle A A reflex angle B A right angle C Which Angle Is This?

18. A straight angle A

19. MEASURING ANGLES Mathematics Presentation

20. SEMI-CIRCLE PROTRACTOR We can use a protractor to help us measure angles! This is a semi-circle protractor.

21. PROTRACTOR This is a full-circle protractor..

22. Using a Protractor- To use a protractor you line up your end point and bottom ray. Then you can find the degree of the angle by looking at the top ray.

23. NAMING AN ANGLE There are three ways to name an angle. You can name an angle by its vertex, by the three points of the angle (the middle point must be the vertex), or by a letter or number written within the opening of the angle.

24. ANGLE PAIRS

25. ADJACENT ANGLES

26. VERTICAL opposite ANGLES

27. COMPLEMENTARY ANGLES

28. SUPPLEMENTARY ANGLES

29. LINEAR PAIR OF ANGLES

30. Examples a) Find the missing angles, diagrams are not drawn accurately: 124˚ 180 - 124 = 56˚ x˚ Adjacent angles on a straight line sum to 180˚ b) 101˚ 101 + 112 + 52 = 265˚ x˚ Angles at a point sum to 360˚ 112˚ 52˚ 360 - 265 = 95˚

31. 1. 2. 3. 4. 131˚ Practice questions Find the missing angles, diagrams are not drawn accurately: 117˚ x˚ x˚ 109˚ 27˚ 46˚ x˚ 116˚ x˚