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# Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m.

Q : 2    Find the total surface area of a cone, if its slant height is $\small 21\hspace{1mm}m$ and diameter of its base is $\small 24\hspace{1mm}m$

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Given,

Base diameter of the cone = $d=24\ m$

Slant height = $l=21\ cm$

We know, Total surface area of a cone = Curved surface area + Base area

$= \pi r l + \pi r^2 = \pi r (l + r)$

$\therefore$  Required total surface area of the cone=

$\\ = \frac{22}{7}\times\frac{24}{2}\times(21+12) \\ \\ =\frac{22}{7}\times\frac{24}{2}\times33 \\ = 1244.57 \ m^2$

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