1. Calculating Angles
This Photo by Unknown Author is licensed under CC BY-SA-NC
This Photo by Unknown Author is licensed under CC BY
This Photo by Unknown Author is licensed under CC BY-SA

2. What are We going to do today
How to calculate angles on a straight line
About a point
Vertically opposite angles
What are We going to do today

3. Warm up Q4. Q3. Q1. Q5. Q2. An angle = 90 degrees?
An angle greater than 90 but less than 180?
An angle less than 90 degrees?
Q1.
An angle is measured in what?
Q5.
An angle greater than 180?
Q2.
An angle = 90 degrees?

4. Angles on a straight lineb a
180o
What do angles on a straight line add up to?? b
40o b
110o
130o a
a = 50o
b = 140o
b = 70o

5. Angles around a point! 360o a = 80o a = 60o b = 170o
Hint: Two straight lines make the same degrees as around a point!
Angles around a point! d a c b
360o
What do angles in a circle add up to??
110o
110o a a
80o
80o
300o
90o b
a = 80o
a = 60o
b = 170o

6. 180

7. 360

8. 30
150

9. 60
120

10. 90

11. 340 20

12. 335 25

13. 80 10

14. 20 30 40

15. 130 50

16. 85 95

17. 10
285 65

18. 270

19. 30 10
320

20. To calculate angles on a straight line and around a point
To calculate angles on a straight line and around a point. To find vertically opposite angles.

21. Opposite angles! a = c d = b Equal! c = 120o b = 40o a = 110o b = 70o
What do we think angles that are opposite each other are?
Equal!
120o a b b
40o c
70o
110o
c = 120o
b = 40o
a = 110o
b = 70o

22. Opposite angles! Now you have a go! How many can you do in 5min? 37o