Diameter of the base of a cone is $ 10.5 \mathrm{~cm} $ and its slant height is $ 10 \mathrm{~cm} $. Find its curved surface area.

AcademicMathematicsNCERTClass 9

Given:

Diameter of the base of a cone is \( 10.5 \mathrm{~cm} \) and its slant height is \( 10 \mathrm{~cm} \).

To do:

We have to find its curved surface area.

Solution:

We have the diameter of the base of the cone $=10.5\ m$

We know that,

Radius$=\frac{diameter}{2}$

This implies,

The radius of the base of the cone$=\frac{10.5}{2}$

$=5.25\ cm$

We also have the slant height of the cone $=10\ cm$

Therefore,

The curved surface area of the cone $=\pi r l$

$=\frac{22}{7} \times 5.25 \times 10$

$=\frac{22}{7}\times52.5$

$=165 \mathrm{~cm}^{2}$

Hence,

The curved surface area of the cone is $165 \mathrm{~cm}^{2}$.

raja
Updated on 10-Oct-2022 13:46:36

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