WAEC Mathematics Past Questions & Answers - Page 125

621.

In the diagram, QR//ST, /PQ/ = /PR/ and < PST = 75^o. Find the value of y

105^o

110^o

130^o

150^o

View answer & explanation

Correct answer is A

In \(\bigtriangleup\) PQR,

Q = S = 75^o (Corresponding angle)

R = Q = 75^o (Base angles of an isosceles \(\bigtriangleup\))

But, y + 75^o = 180^o (Sum of angles in a straight line)

y = 180 - 75

y = 105^o

622.

What is the value of m in the diagram?

20^o

30^o

40^o

50^o

View answer & explanation

Correct answer is B

4m - 15^o = m + 75^o

(Vertically opposite angles are equal)

4m - m = 75 + 15

3m = 90

m = \(\frac{90}{3}\)

m = 30^o

623.

The bar chart shows the marks distribution in am English test. What percentage of the students had marks ranging from 35 to 50?

55\(\frac{1}{3}\)%

60%

65%

66\(\frac{2}{3}\)%

View answer & explanation

Correct answer is D

Percentage of students with marks ranging from 35 to 50 = \(\frac{f_{35} + f{40} + f{50}}{\sum f}\)

= \(\frac{35 + 40 + 45}{20 + 35 + 40 + 45 + 25 + 15}\) x 100%

= \(\frac{120}{180}\) x 100%

= 66\(\frac{2}{3}\)%

624.

The bar chart shows the marks distribution in am English test. If 50% is the pass mark, how many students passed the test?

100

View answer & explanation

Correct answer is B

Pass mark = 50%

No. of students that passed = f₅₀ + f₆₅ + f₈₀

= 45 + 25 + 15

= 85

625.

In the diagram, < PSR = 220^o, < SPQ = 58^o and < PQR = 41^o. Calculate the obtuse angle QRS.

90^o

100^o

121^o

60^o

View answer & explanation

Correct answer is C

Joining SQ. In \(\bigtriangleup\) SPQ,

(22^o + a) + 55^o + (41^o + b) = 180^o

121^o + a + b = 180^o

a + b = 180 - 121

a + b = 59^o.....(1)

In \(\bigtriangleup\) SRPQ; R + a + b = 180^o

R + 59^o = 180^o

(in (1), a + b = 59^o)

R = 180 - 59

R = 121^o