JAMB Mathematics Past Questions & Answers - Page 129

641.

In the diagram, PQ and RS are chords of a circle centre O which meet at T outside the circle. If TP = 24cm. TQ = 8cm and TS = 12cm, find TR.

A.

16cm

B.

14cm

C.

12cm

D.

8cm

Correct answer is A

PT x QT = TR x TS

24 x 8 = TR x 12

TR = \(\frac{24 \times 8}{12}\)

= = 16cm

642.

In the figure, find angle x

A.

100o

B.

120o

C.

60o

D.

110o

E.

140o

Correct answer is E

In the figure, angle x = 20o + 80o + 40o

= 140o

643.

In the figure, the area of the shaded segment is

A.

3\(\pi\)

B.

9\(\frac{\sqrt{3}}{4}\)

C.

3 \(\pi - 3 \frac{\sqrt{3}}{4}\)

D.

\(\frac{(\sqrt{3 - \pi)}}{4}\)

E.

\(\pi + \frac{9 \sqrt{3}}{4}\)

Correct answer is C

Area of sector = \(\frac{120}{360} \times \pi \times (3)^2 = 3 \pi\)

Area of triangle = \(\frac{1}{2} \times 3 \times 3 \times \sin 120^o\)

= \(\frac{9}{2} \times \frac{\sqrt{3}}{2} = \frac{9\sqrt {3}}{4}\)

Area of shaded portion = 3\(\pi - \frac{9\sqrt {3}}{4}\)

= 3 \(\pi - 3 \frac{\sqrt{3}}{4}\)

644.

The figure is an example of the construction of a

A.

perpendicular bisector of a given straight line QR

B.

perpendicular from a given point to a given line QR

C.

perpendicular to a line from a given point P on that line

D.

given angle

Correct answer is B

QR is a given line and P is a given point. The construction is the perpendicular from a given point P to a given line QR

645.

In the figure, find the value of x

A.

110o

B.

100o

C.

90o

D.

80o

Correct answer is C

Z = X = Y = 180o .........(i)

2Z + Y + Y = 190 = 2Z + 2Y = 180

Z + Y = 90o........(ii)

hence x + (z + y) = 180

x + 90o = 180o

x = 180o - 90o

= 90o