A small indoor greenhouse (herbarium) is made entirely of glass panes (including base) held together with tape. It is $ 30 \mathrm{~cm} $ long. $ 25 \mathrm{~cm} $ wide and $ 25 \mathrm{~cm} $ high.
(i) What is the area of the glass?
(ii) How much of tape is needed for all the 12 edges?

AcademicMathematicsNCERTClass 9

Given:

The length of the greenhouse $l$ $=30\ cm$.

The breadth of the greenhouse $b$ $=25\ cm$.

The height of the greenhouse $h$ $=25\ cm$.

To do:

We have to find:
(i) The is the area of the glass.
(ii) The tape needed for all the 12 edges.

Solution:

The area of the glass $=2lb+2bh+2lh$

$=2{lb+bh+lh}$

This implies,

$=2{30\times25}+{25\times25}+{30\times25}$

$=2{750+625+750}$

$=(2\times2125)$

$=4250\ cm^2$

Therefore,

The area of the glass is $4250\ cm^2$.

(ii) The total length of the tape required $=$sum of the lengths of the edges of the greenhouse

$=4\times l+4\times b+4\times h$

$=4(l+b+h)$

$=4(30+25+25)$

$=320\ cm$

Therefore,

The total length of the tape required for all the 12 edges is $320\ cm$.

raja
Updated on 10-Oct-2022 13:42:09

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