314 Trigonometry (Chapter 15)
For the right angled triangle with angleμ:
² thehypotenuse (HYP)is the longest side
² theopposite (OPP)side is oppositeμ
² theadjacent (ADJ)side is adjacent toμ.
Given a right angled triangle ABC with angles ofμandÁ:
For angleμ, BC is theopposite side
AB is theadjacent side.
For angleÁ, AB is theopposite side
BC is theadjacent side.
Example 1 Self Tutor
For the triangle shown, name:
a the hypotenuse
b the side oppositeμ
c the side adjacent toμ:
a The hypotenuse is QR.
(the longest side, opposite the right angle)
b PQ
c PR
Example 2 Self Tutor
For this triangle name the:
a hypotenuse b side opposite angle®
c side adjacent® d side opposite ̄
e side adjacent ̄
a QR (opposite the right angle)
b PR
c PQ
d PQ
e PR
LABELLING SIDES OF A RIGHT ANGLED
TRIANGLE [8.1]
A
In any right angled triangle,
locate the hypotenuse first. Then
locate the opposite side for the
angle you are working with.
μ
Á
®
̄
is theta
is phi
is alpha
is beta
q
OPP
ADJ
HYP
AB
C
q
f
hypotenuse
q
P
Q R
a
b
R
P Q
q
P
Q R
OPP ADJ
a
R
P Q
OPP
ADJ
b
R
P Q
OPP
ADJ
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Y:\HAESE\IGCSE01\IG01_15\314IGCSE01_15.CDR Friday, 26 September 2008 2:20:50 PM PETER