194 Basic Engineering Mathematics
12. In Figure RT8.7, determine angles x, y and z.
(3)
598
y
z
x
378
Figure RT8.7
13. In Figure RT8.8, determine angles a to e.
(5)
c e
a
b
d
608
1258
Figure RT8.8
14. In Figure RT8.9, determine the length of AC.
(4)
D
A
C
E
B
3 m
10 m
8 m
Figure RT8.9
15. In triangle J K L in Figure RT8.10, find
(a) the length K J correct to 3 significant figures.
(b) sin L and tan K , each correct to 3 decimal
places.
(4)
K
L
J
1 1 . 6 0
5.91
Figure RT8.10
16. Two ships leave a port at the same time. Ship X
travels due west at 30 km/h and ship Y travels due
north. After 4 hours the two ships are 130 kmapart.
Calculate the velocity of ship Y .
( 4 )
17. If sin A =
12
37
, find tan A in fraction form.
(3)
18. Evaluate 5 tan 62 ◦ 11 correct to 3 significant
figures.
(2)
19. Determine the acute angle cos −1 0.3649 in degrees
and minutes.
(2)
20. In triangle P Q R in Figure RT8.11, find angle P
in decimal form, correct to 2 decimal places. (2)
P
Q
R
15.2
2 9 .6
Figure RT8.11
21. Evaluate, correct to 3 significant figures,
3 tan 81.27 ◦ − 5 cos 7.32 ◦ − 6 sin 54.81 ◦ .
(2)
22. In triangle ABC in Figure RT8.12, find lengths
AB and AC, correct to 2 decimal places.
(4)
A
B
C
6
408 359
Figure RT8.12
23. From a point P, the angle of elevation of a 40 m
high electricity pylon is 20 ◦ . How far is point P
from the base of the pylon, correct to the nearest
metre?
(3)