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# In Fig. 13.12, you see the frame of a lampshade. It is to be covered with a decorative cloth. The frame has a base diameter of 20 cm and height of 30 cm. A margin of 2.5 cm is to be given for folding it over the top and bottom of the frame.

Q : 10    In Fig. $\small 13.12$, you see the frame of a lampshade. It is to be covered with a decorative cloth. The frame has a base diameter of $\small 20\hspace{1mm}cm$ and height of $\small 30\hspace{1mm}cm$. A margin of $\small 2.5\hspace{1mm}cm$ is to be given for folding it over the top and bottom of the frame. Find how much cloth is required for covering the lampshade.

Views

Daimeter of the base = $d = 20\ cm$

Height of the cylinder  = $30\ cm$

Total height of lampshade= $(30+ 2.5 + 2.5) = 35\ cm$

We know,

Curved surface area of a cylinder of radius $r$ and height  $h$ = $2\pi r h$

Now, Cloth required for covering the lampshade = Curved surface area of the cylinder

$\\ = 2\times\frac{22}{7} \times10 \times 35 \\ \\ = 22\times10\times10 = 2200\ cm^2$

Therefore, $2200\ cm^2$ cloth will be required for covering the lampshade.

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