# A small indoor greenhouse (herbarium) is made entirely of glass panes (including base) held together with tape.

Question. A small indoor greenhouse (herbarium) is made entirely of glass panes (including base) held together with tape. It is 30 cm long, 25 cm wide and 25 cm high.

(i) What is the area of the glass?

(ii) How much of tape is needed for all the 12 edges?

Solution:

(i) Length $(l)$ of green house $=30 \mathrm{~cm}$

Breadth $(b)$ of green house $=25 \mathrm{~cm}$

Height $(h)$ of green house $=25 \mathrm{~cm}$

Total surface area of green house

$=2[1 b+1 h+b h]$

$=[2(30 \times 25+30 \times 25+25 \times 25)] \mathrm{cm}^{2}$

$=[2(750+750+625)] \mathrm{cm}^{2}$

$=(2 \times 2125) \mathrm{cm}^{2}$

$=4250 \mathrm{~cm}^{2}$

Therefore, the area of glass is $4250 \mathrm{~cm}^{2}$.

It can be observed that tape is required along side AB, BC, CD, DA, EF, FG, GH, HE, AH, BE, DG, and CF.

Total length of tape $=4(l+b+h)$

$=[4(30+25+25)] \mathrm{cm}$

$=320 \mathrm{~cm}$

Therefore, $320 \mathrm{~cm}$ tape is required for all the 12 edges.