JAMB Mathematics Past Questions & Answers - Page 116

576.

If the diagram is the graph of y = x2, the shaded area is

A.

64 square units

B.

\(\frac{126}{4}\) square units

C.

32 square units

D.

\(\frac{64}{3}\) square units

Correct answer is D

A = \(\int^{x = 4}_{x = 0}\) ydx = \(\int^{4}_{0}\) x2dx = [\(\frac{x^3}{3} + c]^{4}_{0}\)

= \(\frac{64}{3}\) square units

577.

In the diagram, EFGH is a circle centre O. FH is a diameter and GE is a chord which meets FH at right angle at the point N. If NH = 8cm and EG = 24cm, calculate FH

A.

32cm

B.

26cm

C.

20cm

D.

16cm

Correct answer is B

\(\bigtriangleup\)OEN = \(\bigtriangleup\)OGN

OE = OG = r(radii)

(r - 8)2 + 122 = r2

r2 - 16r + 64 + 144 = r2

16r = 64 + 144 = r2

16r = 64 + 144 = 208

\(\frac{208}{16}\) = 13cm

FH = 2FO = 2OH = 2R

= 2 x 13cm

= 26cm

578.

In the diagram, If < RPS = 50o, < RPQ = 30o and pq = QR, Find the value of < prs

A.

50o

B.

60o

C.

70o

D.

80o

Correct answer is C

< QPR = < PRQ = 30o (PQ = QR)

< SPQ + < QRS = 180o (supplementary)

80 + < QRS = 180o = < QRS = 180o - 80o = 100o

< QRP + < PRS = 100o = 30o + < PRS = 100o

= < PRS = 100o - 30o = 70o

579.

The grades of 36 students in a class test are as shown in the pie chart. How many student has excellent?

A.

7

B.

8

C.

9

D.

12

Correct answer is A

degree of excellent in the pie-chart = 360o - (90o + 120o + 80o) = 360o - 290o = 70o

= 360o = 36 students

70 = \(\frac{70^o}{360^o}\) x 36 = 7

580.

find the length XZ in the triangle

A.

\(\sqrt{7m}\)

B.

\(\sqrt{6m}\)

C.

\(\sqrt{5m}\)

D.

\(\sqrt{3m}\)

Correct answer is A

xz2 = xy2 + yx2 - 2(xy) (yz) cos 120o

= 22 + 12 - 2(2) (1) cos 1202

= 4 + 1 - 4x - cos 60 = 5 - 4x - \(\frac{1}{2}\)

5 + 2 = 7

xz = \(\sqrt{7}\)m