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A joker’s cap is in the form of a right circular cone of base radius 7 cm and height 24 cm. Find the area of the sheet required to make 10 such caps.


Answer :

Given :
Radius (r) of conical cap = 7 cm
Height (h) of conical cap = 24 cm

Slant height (l) of the conical cap
\(\Rightarrow \) \({l}^2 = {h}^2 + {r}^2\)
\(\Rightarrow \) \(l^2= {7}^2 + {24}^2\) \({cm}^2\)
\(\Rightarrow \) \(l^2= 625\) \({cm}^2\)
\(\Rightarrow \) \({l}^2 = {25}^2 cm\)
\(\Rightarrow \) l = 25 cm

Therefore, the slant height Of the tent is 25 cm.

We know, CSA of tent
= \({\pi}rl\)
= [\(\frac{22}{7} × 7 × 25\) \({cm}^2\)]
= [\(22 × 1 × 25\) \({cm}^2\)]
= \(550\) \({cm}^2\)

Thus, CSA of 10 such caps
= (10 x 550) \({cm}^2\)
= 5500 \({cm}^2\)

\(\therefore \) 5500 \({cm}^2\) sheet will be required.

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