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?​

Answer 1

Answer:

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Given :-

herbarium is like a cuboid.

Here, length (l) = 30 cm,

breadth (b) = 25 cm,

height (h) = 25 cm

(i) Surface area of the herbarium (glass)

= 2[lb + bh + hl]

= 2[(30 x 25) + (25 x 25) + (25 x 30)] cm2 – 2[750 + 625 + 750] cm²

= 2[2125] cm²

= 4250 cm²

Thus, the required area of the glass = 4250 cm2

(ii) Total length of 12 edges = 4l + 4b + 4h

= 4(l + b + h)

= 4(30 + 25 + 25) cm

= 4 x 80 cm = 320 cm

Thus, the required length of tape = 320 cm

Answer 2

Answer:

Given:

⇒l=30,b=25,h=25

(i) Total S.A of green house

=2(lb+bh+lb)

=2(30×25+30×25+25×25)

=4250 cm

2

(ii) For 12 edges: Total length

=4l+4b+4h

=4(30+25+25)

=320 cm