Question

A right circular cone of radius 3 cm had a curved surface area of 47.1 cm². Find the volume of the cone. ( Use π = 3.14)

Answer 1

Let the height and the slant height of the cone be h and l respectively. It is given that the radius of the base r = cm.
$it \: is \: also \: given \: that \: curved \: surface \: area \: of \: the \: cone \: is \: 47.1 \: cm {}^{2} \\ \\ therefore \\ \\ \pi \times \: r \times l = 47.1 \\ \\ = > 3.14 \times 3 \times l = 47.1 \\ \\ = > l = \frac{47.1}{9.42} = 5 \: cm \\ \\ therefore \\ \\ l {}^{2} =r {}^{2} + h {}^{2} \\ \\ = > {5}^{2} = {3}^{2} + h {}^{2} \\ \\ = > 25 + 9 + {h}^{2} \\ \\ = > h {}^{2} = 16 \\ \\ = > h = \sqrt{16} = 4 \: cm \\ \\ therefore \: volume \: of \: the \: cone \\ \\ = \frac{1}{3} \times \pi \: \times r {}^{2} \times h \\ \\ = \frac{1}{3} \times 3.14 \times {3}^{2} \times 4 \\ \\ = 3.14 \times 3 \times 4 \\ \\ = 37.68 \: cm {}^{2}$


hope it helps....

Answer 2

Answer:

Step-by-step explanation:

Hey mate ,

Here is your correct answer......BRO..

Radius of right circular cone = 3 cm.

C.S.A = 47.1 cm^2 .

C.S.A of right circular cone = pie r l.

47.1 = 22/7 × 3 × l( slant height).

L( slant height) = 47.1 × 7 / 22 × 3 cm.

= 45 cm (approximately )

H^2 = root (3)^3 + (45)^2

= 45 cm..

So, Volume = 1/3 pie r^2 h

= 1/3 × 22/7 × 3 × 3 × 45

= 425cm^2 ( approximately)....