Question

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Answer 1

• The lateral surface area of the right circular cone = 2310 cm².

Given :

• The height of the right circular cone = 28 cm.
• The base radius of the right circular cone = 21 cm.

To Find :

• The lateral surface area of a right circular cone.

Solution :

We have to find the lateral surface area of the right circular cone.

We know that,

$\boxed{ \bf L.S.A. = \pi r \sqrt{ {r}^{2} + {h}^{2}} }$

Where,

• L.S.A. = Lateral surface area of the right circular cone.
• r = radius of the right circular cone.
• h = height of the right circular cone.

We have,

• r = 21 cm.
• h = 28 cm.

Substitute both the given values in the formula of lateral surface area (L.S.A.) of the right circular cone.

$\bf \implies \dfrac{22}{ \not7} \times \not21 \: cm \sqrt{ {(21 \: cm)}^{2} + {(28 \: cm)}^{2} } \\ \\ \\ \bf \implies 22 \times 3 \sqrt{441 \: {cm}^{2} + 784 \: {cm}^{2} } \\ \\ \\ \bf \implies 22 \times 3 \sqrt{1225 \: {cm}^{2} } \\ \\ \\ \bf \implies 66 \: cm\times 35 \: cm \\ \\ \\ \bf \implies 2310 \: {cm}^{2} \\ \\ \\ \: \: \bf\therefore \: \: L.S.A. = 2310 \: {cm}^{2}$

Hence,

The lateral surface area of the right circular cone is 2310 cm².