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

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

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?

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

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

180

360

30 150

60 120

90

340 20

335 25

80 10

20 30 40

130 50

85 95

10 285 65

270

30 10 320

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.

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

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