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WAEC Mathematics Past Questions & Answers - Page 39

191.

In the diagram, RT is a tangent to the circle at R, < PQR = 70o, < QRT = 52o, < QSR and < PRQ = x. Calculate the value of x.

A.

70o

B.

58o

C.

55o

D.

48o

Correct answer is B

x = 180o - (52o + 70o)

= 180o - 122o

= 58o 

192.

In the diagram, RT is a tangent to the circle at R, < PQR = 70o, < QRT = 52o, < QSR and < PRQ = x. Find the value of y. 

A.

70o

B.

60o

C.

52o

D.

18o

Correct answer is C

∠QRT = ∠SRT = 52 (opposite angles)

∠SRT = y = 52 (alternate angles)

y = 52o 

193.

In the diagram, O is the centre of the circle of radius 18cm. If < zxy = 70o, calculate the length of arc ZY. [Take π=227]
 

A.

11cm

B.

22 cm

C.

44 cm

D.

80 cm

Correct answer is C

ZOT = 2 x 70o 140o

Length = θ360 x 2πr

140o360×2×227 x 18

= 44cm

195.

If tan x = 34, 0 < x < 90o, evaluate cosx2sinx 

A.

83

B.

32

C.

43

D.

23

Correct answer is D

y2 = 32 + 42

y2 = 9 + 16 

y = 25 

= 5

cosx2sinx=45+2×35

= 45×56

= 23