1. Introduction into trigonometry Born: 190 BC in Nicaea, Bithynia (now Turkey) Died: 120 BC in probably Rhodes, Greece Hipparchus of Rhodes Hipparchus Compiled a trigonometric table for solving triangles. Today we have all the values saved on computers : The calculator!

2. Example Work out the lettered lengths for each of the following right angled triangles, giving your answers to 1 decimal place: (i) 25° 14 cm k

3. 47° 21 cm a (ii)

4. 63° 18 cm b (iii)

5. 75°21 cm t (iv)

6. 9° 5 m c (v)

7. Example Given triangle ABC below work out the length of BC, giving your answer to 3 significant figures. AB C 78 mm 59°

8. Example A piece of gutter pipe is 350cm long is angled at 6° to the horizontal. How much higher is the upper end of the guttering than its lower end?

9. Example When a set of ladders of length 13m are placed against a vertical wall they make an angle of 68° with the horizontal. How far up the wall does the ladder reach?

10. 10cm 70° Example For the isosceles triangle below, find the length of the third side, giving your answer correct to 2 decimal places.