WAEC Mathematics Past Questions & Answers - Page 95

471.

Using the venn diagram, find n(x \(\cap\) y¹)

View answer & explanation

Correct answer is A

(x \(\cap\) y²) = [a, b]

n(x \(\cap\) y²) = 2

472.

In the diagram, ST//PQ reflex angle SRQ = 198^o and < RQp = 72^o. Find the value of y

18^o

54^o

87^o

92^o

View answer & explanation

Correct answer is B

R +198 = 360(angles at a point)

R = 360 - 198 = 162^o

C = 72(alternate angle), b + c = 180(angles or straight line)

b = 190 - c = 180 - 72 = 108

a + b = R = 162

a = R - b = 162 - 108

= 54, but a = y(alternate angles)

y = 54^o

473.

In the diagram, PQ is a straight line. Calculate the value of the angle labelled 2y

130^o

120^o

110^o

100^o

View answer & explanation

Correct answer is D

Sum of angles on straight line = 180^o

80^o + 50^o + x + 10^o = 180^o

140^o + x = 180^o

x = 180^o - 140^o

x = 40^o

total sum of all angles = 360^o

2y^o + 2x^o + 80^o + 50^o + x + 10^o = 360^o

2y^o + 2(40)^o + 80^o + 50^o + 40 + 10 = 360^o

2y^o + 80 + 180^o = 360^o

2y^o + 260^o = 360^o

2y^o = 360^o - 260^o

2y^o = 100^o

angle 2y^o = 100^o

474.

In the diagram, PQRST is a regular polygon with sides QR and TS produced to meet at V. Find the size of < RVS

36^o

54^o

60^o

72^o

View answer & explanation

Correct answer is A

PQRST is a regular polygon with 5 sides-pentagon n = 5, Each exterior angle = \(\frac{360^o}{n}\)

= \(\frac{350}{5}\) = 70^o

Each interior angle = 180 - 72^o

(< s on str. line) = 180^o

Since the pentagon is regular, the exterior angles are equal < R = 72^o and < S = 72^o

< RVS = 180^o - (< R + < S)

= 180^o - (72^o + 72^o)

= 180^o - 144^o

= 36^o