2002 - JAMB Mathematics Past Questions and Answers - page 6

A_{(\text{shaded portion})} = (\pi R^2 - \pi r^2) r = (\frac{2}{5})R

A_{(\text{shaded portion})} = (\pi R^2 - \pi (\frac{2}{3} R)^2 = \pi R^2 - \frac{4 \pi R^2}{25})

= (\pi R^2(1 - \frac{2}{3}) = \frac{21}{25} \pi R^2)

V = (\pi r^2 h + \frac{2}{3} \pi r^3)

N.B h = r

V = (\pi x (3)^2) x 20 = (\frac{2}{3} \times \pi \times (3)^3)

180(\pi + 18 \pi = 198cm^3)

< QPS = < QSP = QRS = X

since PQ = QS = RS

< RQS = 2x - exterior angle

< RSQ = 180 - x

2x + x(188 - x) = 180

3x + 108 - x = 180 - x

2x + 108 = 180

2x = 180 - 108 = 72

x = (\frac{72}{2})

= 36^o