1990 - WAEC Mathematics Past Questions and Answers - page 4

31

In the diagram above PS||RQ, |RQ| = 6.4cm and perpendicular PH = 3.2cm. Find the area of SQR

A
5.12cm2
B
9.60cm2
C
10.24cm2
D
20.48cm2
correct option: c

Area of a triangle = \(\frac{1}{2} \times b \times h\)

Area of \(\Delta\) SQR = \(\frac{1}{2} \times 6.4 \times 3.2\)

= 10.24 cm\(^2\)

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32

Which angle is equal to ∠VWZ?

A
∠VXZ
B
∠VYX
C
∠XZW
D
∠YXZ
correct option: a

< VWZ = < VXZ (angles in the same segment)

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33

Which triangle is equal in area to ΔVWZ

A
ΔVXZ
B
ΔVYZ
C
ΔXYV
D
ΔWYV
correct option: b

Area of \(\Delta\) VYZ = Area of \(\Delta\) VWZ (same base and within same parallel)

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34
In the diagram above, PQRS s a cyclic quadrilateral, ∠PSR = 86o and ∠QPR = 38o. Calculate PRQ
A
58o
B
53o
C
48o
D
43o
correct option: c
PQR = 180o - 86o = 94o
∴PRQ = 180o - 94o - 36o = 48o
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35
In the diagram below, O is the center of the circle if ∠QOR = 290o, find the size ∠QPR
A
110o
B
70o
C
55o
D
35o
correct option: d
360o - 290o = 70o
70/2 = 35o
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36

In the diagram above, PQ is a tangent at T to the circle ABT. ABC is a straight line and TC bisects ∠BTO. Find x.

A
20o
B
30o
C
35o
D
40o
correct option: e

From the figure < TAB = < BTQ = 40° (alternate segment)

\(\therefore\)< ATB = 180° - (70° + 40°) = 70° (angle on a straight line)

< BTC = \(\frac{40°}{2} = \frac{< BTQ}{2}\)

\(\therefore < BTQ = 40°\)

x° = 180° - (40° + 70° + 20°) 

= 50° 

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37
Which of the sketches above gives a correct method for constructed an angle of 120o at the point P?
A
I only
B
II only
C
III only
D
I and II only
correct option: d
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38

Use mathematical table to evaluate (cos40° - sin30°)

A
-0.2660
B
-0.0266
C
0.0266
D
0.2660
correct option: d

(cos 40° - sin 30°)

= 0.7660 - 0.5

= 0.2660

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39
If the shadow of a pole 7m high is 1/2 its length what is the angle of elevation of the sun, correct to the nearest degree?
A
90o
B
63o
C
60o
D
26o
correct option: b
tan θ - 7/3.5 = 2
tan θ= 2.0000
θ = 63o
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40
From the top of a building 10m high, the angle of depression of a stone lying on the horizontal ground is 69o. Calculate ,correct to one decimal place, the distance of the stone from the foot of the building
A
3.6m
B
3.8m
C
6.0m
D
9.3m
correct option: b
tan21o =x/10
x = 10 tan 21o
= 3.3839 = 3.8m
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