1. The Sine Rule 50 0 60 0 A B C 100km Find the length of CB None of the trigonometric rules we currently know will help us here. We will split triangle ABC into two right angled triangles by adding an altitude CD. D

2. 50 0 60 0 A B C 100km D b h A C D h D C B In the same way;

3. 50 0 60 0 A B C 100km Find the length of CB Using the sine rule; ?

4. b) In triangle RST calculate ST. 110 0 30 0 R ST 15cm Using the sine rule; ?

5. Page 126 Exercise 1

6. Calculating An Angle Calculate  ABC and  BAC. A BC 120 0 9cm 3cm Using the sine rule;

7. Page 127 Exercise 2 Page 128 Exercise 3B

8. Area of a Triangle h h C A B b Which is normally written:

9. Calculate the area of triangle ABC where all lengths are given in cm. A B C 6 3

10. Page 135 Exercise 7

11. Which Formula? GivenSketchUse 3 Sides 2 Sides and the included angle Sides and opposite angle

12. Page 137 Exercise 8A Page 138 Exercise 8B followed by the check up on page 139