1. Try describing the angle of the shaded areas without using degrees

2. Radians What is a Radian? How to convert degrees into Radians How to convert Radians into degrees How to calculate the length of an Arc How to calculate the area of a sector

7. r

8. r

12. Radians r r r A Radian is a unit used to measure angles. One Radian is the angle that cuts out a length of the circumference that’s equal to the radius 1 rad

14. Radians Quick facts to remember! There is π rads (or 3.14 rads) in half a circle, and 2π rads in one full circle. How many degrees is there in 1 radian then?

15. Radians or Degrees? Changing from Radians or Degrees use these rules From Radians to Degrees From Degrees to Radians

16. Degrees to Radians Example What is 30˚ in Radians? What is 90˚ in Radians?

17. Radians to Degrees Examples What is π/3 rad in Degrees? What is 3π/2 rad in Degrees?

18. Question Time Have a go at Q1, 2, and 3 on the back

21. Length of an Arc s s = length of arc r = radius Ө = angle in rad

22. Area of a Sector A = Area of sector r = radius Ө = angle in rad A

23. Question Time Try out Q5, 6 and exam question

26. Independent Study START REVISING FOR C1 MOCK-MOCK TEST