WAEC - Mathematics (1992 - No. 16)
The volume of a cone of height 9cm is 1848cm\(^3\). Find its radius. [Take π = 22/7]
7cm
14cm
28cm
98cm
196cm
توضیح
1/3 πr\(^2\) x 9 = 1848
3 x πr2 = 1848 r2 = 1848/3 x 7/22 r = 14
\(\text{Volume of a cone} = \frac{1}{3} \pi r^2 h\)
\(\frac{1}{3} \times \frac{22}{7} \times r^2 \times 9 = 1848\)
\(r^2 = \frac{1848 \times 7}{22 \times 3}\)
\(r^2 = 196 \therefore r = 14cm\)