WAEC Mathematics Past Questions & Answers - Page 302

1,506.

In the diagram above, O is the center of the circle PQRS and ∠QPS = 36°. Find ∠QOS

A.

36o

B.

72o

C.

108o

D.

144o

E.

288o

Correct answer is B

< QOS = 2 < QPS (angle subtended at the centre)

\(\therefore\) < QOS = 2 x 36° = 72°

1,507.

In the diagram above, TR = TS and ∠TRS = 60o. Find the value of x

A.

30

B.

45

C.

60

D.

120

E.

150

Correct answer is C

∠TRS = ∠RST = 60o
∠PSR + ∠PQR = 180o, 120o + xo = 180o
x = 60o

1,508.

In the diagram above, O is the center of the circle and ∠POR = 126°. Find ∠PQR

A.

234o

B.

117o

C.

72o

D.

63o

E.

54o

Correct answer is B

Reflex < POR = 360° - 126° = 234°

\(\therefore\) < PQR = \(\frac{1}{2} \times 234°\)

= 117°

1,509.

In the diagram above PQT is a tangent to the circle QRS at Q. Angle QTR = 48° and ∠QRT = 95°. Find ∠QRT

A.

48o

B.

45o

C.

37o

D.

32o

E.

30o

Correct answer is C

∠RQT = 180° - (95° + 48°) = 73°
∠OQR = 90° - 37° = 53°
∠QOR = 180° - (53° + 53°) = 74°
QSR = 74°/2 = 37°

1,510.

The diagram above shows the shaded segment of a circle of radius 7cm. if the area of the triangle OXY is 12\(\frac{1}{4}\)cm\(^2\), calculate the area of the segment
[Take π = 22/7]

A.

5/12cm2

B.

7/12cm2

C.

11/6cm2

D.

2 1/3cm2

E.

6 1/6cm2

Correct answer is B

Area of \(\Delta OXY\) = \(12\frac{1}{4} cm^2\)

Area of sector OXY = \(\frac{30}{360} \times \frac{22}{7} \times 7 \times 7\)

= \(\frac{77}{6} = 12\frac{5}{6} cm^2\)

Area of the shaded portion = \(12\frac{5}{6} - 12\frac{1}{4}\)

= \(\frac{7}{12} cm^2\)