CHAPTER 7
Solutions of Triangles
19
=
7
6
3
X
¡
sin
sin
5
•
5
5
=
1
0
4
1
0
8
2
–
(
)
¡
=
1
0
8
–
Ans
cos
=
EFG
is an isosceles triangle in which
°
=
∠
104
FEG
.
FG
is produced to
H
. Find
°
y
cos
.
OPERATION
1
. First calculate
FGE
∠
. While in
COMP/Deg
mode, press
So,
FGE
∠
is equal to 38°.
2
. To determine
°
y
cos
, press
Hence,
°
y
cos
is approximately -0.788.
PQR
is a triangle in which
°
=
∠
55
PQR
,
°
=
∠
63
QPR
and
PR
= 7.5cm.
Find the length of
QR
.
OPERATION
1
. Use the formula
°
=
°
55
sin
5
.
7
63
sin
QR
to determine
QR
. While in
COMP/Deg
mode, press
Hence, the length of
QR
is approximately 8.16cm.
Example 2
7.5Xsin 63
¡
sin 55
8.157885924
63°
55°
7.5cm
P
Q
R
F
E
H
G
104°
y
°
Example 1
(180-104)
¡
2
38
180-Ans
142
cos Ans
-0.788010753