CHAPTER 7 Solutions of Triangles
19
=
¡
sin
•
=
¡
=
cos
=
EFG is an isosceles triangle in which °
104FEG . FG is produced to
H. Find
°ycos .
OPERATION
1. First calculate
FGE∠
. While in COMP/Deg mode, press
So,
FGE∠
is equal to 38°.
2. To determine °ycos , press
Hence,
°ycos is approximately -0.788.
PQR
is a triangle in which
°
55PQR
,
°
63QPR
and PR = 7.5cm.
Find the length of
QR.
OPERATION
1. Use the formula
°
=
° 55sin
5.7
63sin
QR
to determine QR. While in
COMP/Deg mode, press
Hence, the length of
QR
is approximately 8.16cm.
Exam
le 2
7.5Xsin 63¡sin 55
8.157885924
63°
55°
7.5cm
P
Q
R
F
E
H G
104°
y°
Exam
le 1
(180-104)¡2
38
180-Ans
142
cos Ans
-0.788010753