WAEC Past Questions and Answers - Page 4090

20,446.

A cliff on the bank of a river is 300 metres high. if the angle of depression of a point on the opposite side of the river is 60° find the width of the river.

A.

100m

B.

75√3m

C.

100√3m

D.

200√3m

E.

300m

Correct answer is C

No explanation has been provided for this answer.

20,447.

Town P is on bearing 315o from town Q while town R is south of town P and west of town Q. lf town R is 60km away from Q, how far is R from P?

A.

30km

B.

42km

C.

45km

D.

60km

E.

120km

Correct answer is D

No explanation has been provided for this answer.

20,448.

The value of sin 210° is

A.

\(-\frac{1}{2}\)

B.

\(-\frac{\sqrt{3}}{2}\)

C.

\(\frac{1}{2}\)

D.

\(\frac{\sqrt{2}}{2}\)

E.

\(\frac{\sqrt{3}}{2}\)

Correct answer is A

sin 210 = - sin (210 - 180) = - sin 30

= \(-\frac{1}{2}\)

20,449.

The value of tan 315°

A.

1

B.

√2/2

C.

0

D.

-1

E.

-√2/2

Correct answer is D

tan 315° = - tan (360 - 315) = - tan 45 = -1

20,450.

If cos θ = 5/13, what is the value of tan \(\theta\) for 0 < θ < 90° ?

A.

13

B.

5

C.

13/5

D.

12/5

E.

5/12

Correct answer is D

\(\cos \theta = \frac{5}{13}\)

\(\implies\) In the right- angled triangle, with an angle \(\theta\), the adjacent side to \(\theta\) = 5 and the hypotenuse = 13.

\(\therefore 13^2 = opp^2 + 5^2\)

\(opp^2 = 169 - 25 = 144 \implies opp = \sqrt{144}\)

= 12.

\(\tan \theta = \frac{opp}{adj} = \frac{12}{5}\)