Cambridge International Mathematics

EXERCISE 29C.2

1 Find the value ofμ:

abc

2 Solve forx:

abc

de f

3 In triangle ABC, find the measure of:

a angleAif a=12: 6 cm, b=15: 1 cm and AbBC=65o

b angleBif b=38: 4 cm, c=27: 6 cm and ACBb =43o

c angleCif a=5: 5 km, c=4: 1 km and BbAC=71o.

4 In triangle ABC, angleA= 100o, angleC=21o, and AB=6: 8 cm.

Find the length of side AC.

5 In triangle PQR, angleQ=98o,PR=22cm, and PQ=15cm.

Find the size of angleR.

THE COSINE RULE

In any triangle ABC with sidesa,bandcunits and opposite anglesA,BandCrespectively,

a^2 =b^2 +c^2 ¡ 2 bccosA

b^2 =a^2 +c^2 ¡ 2 accosB

c^2 =a^2 +b^2 ¡ 2 abcosC.

D THE COSINE RULE [8.5]

14.8 m 17.5 m

38° q°

29 cm

54°

35 cm

q°

2.4 km

6.4 km

q° 15°

A B

C

b a

c

There may be two

possible solutions.

A sketch may

help to find them.

6m

8m

x°

20°

120°

xcm

9cm

25°

xkm

6km

x°

5m

50°

7m

110°

xm

10 m

10 cm

x° 12 cm

35°

25° 30°

588 Further trigonometry (Chapter 29)

IGCSE01

cyan magenta yellow black

(^05255075950525507595)
100 100
(^05255075950525507595)
100 100
Y:\HAESE\IGCSE01\IG01_29\588IGCSE01_29.CDR Monday, 27 October 2008 2:52:52 PM PETER