WAEC - Mathematics (1995 - No. 25)

Find the total surface area of solid circular cone with base radius 3cm and slant height 4cm. [Take π = 22/7]
37 5/7cm2
66cm2
75 3/7cm2
78 2/7cm2
88cm2

Explanation

T.S.A of a cone = \(\pi r^2 + \pi rl\)

= \(\frac{22}{7} \times 3^2 + \frac{22}{7}  \times 3 \times 4\)

= \(\frac{198}{7} + \frac{264}{7}\)

= \(\frac{462}{7}\)

= 66 cm\(^2\)

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