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
توضیح
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\(^2\)