1. Interior Angles of a Quadrilateral
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Interior Angles of a Quadrilateral

2. Interior Angles of a Quadrilateral
23 February 2019
Interior Angles of a Quadrilateral

3. What is the size of angle A?
Whiteboards
80°
55°
45° A

4. We know the interior angles of a triangle = 180°B C
A + B + C = 180°
What is the total interior angles of a quadrilateral? B A D C

5. A C
180° A B C
180° B
180°
180°
360°

6. A B C
180° A C
180° B
180°
180°
360°

7. The interior angles in a quadrilateral
add up to 360° A B
A + B + C + D = 360° C D

8. The interior angles in a quadrilateral
add up to 360°
110° A
70° B
A + B + C + D = 360°
= 360°
70° C
110° D

9. The interior angles in a quadrilateral
add up to 360°
100° A
100° B
A + B + C + D = 360°
= 360°
80° C
80° D

10. The interior angles in a quadrilateral
add up to 360°
110° B
160° A
A + B + C + D = 360°
= 360°
30° D
60° C

11. The interior angles in a quadrilateral
add up to 360°
80° B
A + B + C + D = 360°
= 360°
30° D
190° A C
60°

12. The interior angles in a quadrilateral
add up to 360°
A + B + C + D = 360°
50° B
= 360°
210° A C
80°
20° D

13. Whiteboards

14. Can you find the missing angle?
80° ?°
100°
100°
80°

15. Can you find the missing angle?
85° ?°
95°
95°
85°

16. Can you find the missing angle?
70° ?°
110°
110°
70°

17. Can you find the missing angle?
110° ?°
110°
75°
75°

18. Can you find the missing angle?
95°
85°
85° ?°
95°

19. Can you find the missing angle?
95° ?°
85°
85°
95°

20. Do the interior angles of a quadrilateral really equal 360°?
Are they
correct?
Do the interior angles of a quadrilateral really equal 360°?
Check the worksheet with a friend!

21. Calculate the missing angle!
78°
102°
100°
75°
80°
80°
105°
102°
105°
85°
75°
120°
50°
60°
114°
114°
105°
40°
85°
66°
20°

22. Measure the interior angles of the quadrilaterals
Measure the interior angles of the quadrilaterals. What do they add up to?

25. Calculate the missing angles.

26. Write a short text message to a
friend describing what you learnt this lesson.