WAEC Mathematics Past Questions & Answers - Page 162

806.

In the diagram P, Q, R, S are points on the circle RQS = 30o. PRS = 50o and PSQ = 20o. What is the value of xo + yo?

A.

260o

B.

130o

C.

100o

D.

80o

Correct answer is B

Draw a line from P to Q

< PQS = < PRS (angle in the sam segment)

< PQS = 50o

Also, < QSR = < QPR(angles in the segment)

< QPR = xo

x + y + 5= = 180(angles in a triangle)

x + y = 180 - 50

x + y = 130o

807.

In the diagram, PR is a diameter of the circle centre O. RS is a tangent at R and QPR = 58o. Find < QRS

A.

112o

B.

116o

C.

122o

D.

148o

Correct answer is C

PRQ = 90 - 58 = 32o(angle in a semi-circle)

Since PRS = 90o(radius angular to tangent)

QRS = 90 + 32

= 122o

808.

In the diagram, \(\frac{PQ}{RS}\), find xo + yo

A.

360o

B.

300o

C.

270o

D.

180o

Correct answer is D

PQR = QRS = Y(alt. amgles)

PQR + x = 180o(angles on a straight line)

y + x = 180o

809.

In the diagram, |QR| = 5cm, PQR = 60<sup>o</sup> and PSR = 45<sup>o</sup>. Find |PS|, leaving your answe in surd form.

A.

4\(\sqrt{5}\)cm

B.

3\(\sqrt{7}\)cm

C.

4\(\sqrt{6}\)cm

D.

5\(\sqrt{6}\)cm

Correct answer is D

tan 6o = \(\frac{|PR|}{|QR|}\)

\(\sqrt{3} = \frac{|PR|}{5}\)

= |PR| = \(5 \sqrt{3}\)cm

sin 45 = \(\frac{|PR|}{|PS|}\)

\(\frac{1}{\sqrt{2}}\) = \(\frac{5 \sqrt{3}}{|PS|}\)

|PS| = \(5 \sqrt{3}\) x \(\sqrt{2}\)

= 5\(\sqrt{6}\)cm

810.

In the diagram, PQUV, PQTU, QRTU and QRST are parallelograms. |UV| = 4.8cm and the perpendicular distance between PR and VS is 5cm. Calculate the area of quadrilateral PRSV

A.

96cm2

B.

72cm2

C.

60cm2

D.

24cm2

Correct answer is C

|VU| = |UT| = |TS|

|VS| = (4.8) x 3 = 14.4cm

|PQ| = |QR| = 4.8

|PR| = (4.8) x 2 = 9.6cm

Since quad. PRSV is a trapezium of height 5cm

Area of quad. PRSV = \(\frac{1}{2}(a + b)h\)

= \(\frac{1}{2}(14.4 + 9.6) \times 5\)

= \(\frac{1}{2}(24) \times 5\)

12 x 5 = 60cm2