Cambridge International Mathematics

Trigonometry (Chapter 15) 315

EXERCISE 15A

1 For the triangles given, name:

i the hypotenuse ii the side opposite angleμ iii the side adjacent toμ

abc

de f

2 For the triangle given, name the:

i hypotenuse ii side opposite® iii side adjacent to®

iv side opposite ̄ v side adjacent to ̄

ab

Discovery 1 Ratio of sides of right angled triangles

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In this discovery we will find the ratios

OPP

HYP

,

ADJ

HYP

and

OPP

ADJ

in a series of triangles which

are enlargements of each other.

What to do:

1 Consider four right angled triangles ABC

where CbAB is 30 oin each case but the sides

vary in length.

By accurately measuring to the nearest

millimetre, complete a table like the one

following:

K q

L

C M

A q B

q

P Q

q

X

Y

Z

q

C

E D

R

q

R

S T

P Q

R

a

b

A b a

B

C

A B

1

C 1

B 2

C 2

B 3

C 3

B 4

C 4

30°

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Y:\HAESE\IGCSE01\IG01_15\315IGCSE01_15.CDR Friday, 26 September 2008 2:27:59 PM PETER