Question

. Find the volume of a cone whose diameter is 30m and slant height is 25m.​

Answer 1

Answer:

$volume \: of \: cone = \frac{1}{3} \pi \: r ^{2} h \\ where \: r = radius \: and \: \\ h = height \\ here \: diameter = 30m \: \\ thus \: radius = \frac{30}{2} = 15m \\ slant \: height \: (l) = 25m(given) \\ by \: pythagoras \: theorem \\ \\ l = \sqrt{ {r}^{2} + {h}^{2} } \\ thus \: h = \sqrt{l^{2} - {r}^{2} } \\ h = \sqrt{25^{2} - {15}^{2} } \\ h = \sqrt{625 - 225} \\ h = \sqrt{400} \\ h = 20m \\ \\ now \: r = 15m \: and \: h = 20m \\ thus \: volume \: of \: cone = \\ \frac{1}{3} \times \frac{22}{7} \times {15}^{2} \times 20 \\ = 4714.29 {m}^{3} (approx)$