Question

The length, breadth, and height of a rectangular box are 80 cm, 40 cm, and 20 cm, respectively. If a square paper of 40 cm length is to be glued on it, how many such papers will be required?​

Answer 1

Question :-

The length, breadth, and height of a rectangular box are 80 cm, 40 cm, and 20 cm, respectively. If a square paper of 40 cm length is to be glued on it, how many such papers will be required?

Given :-

• length :- 80cm

• breath :- 40cm

• height :- 20cm

To find :-

• how many papers are required

Formula :-

• surface area of the box = 2(lb + BH + HL)

• area of square = (side)²

Solution :-

• by using Frist formula :-

surface area of the box = 2(lb + BH + HL)

$\longrightarrow \sf \: tsa \: of \: cuboid \: = 2(lb + bh + hl) \\ \\ \\ \longrightarrow \sf \: 2(80 \times 40 + 40 \times 20 + 20 \times 80) \\ \\ \\ \longrightarrow \sf \: 2(3200 + 800 + 1600) \\ \\ \\ \longrightarrow \sf \: 2(5600) = 11200 {cm}^{2}$

• now, by using 2nd formula :-

$\longrightarrow \sf \: area \: of \: sq \: paper \: = {side}^{2} \\ \\ \\ \longrightarrow \sf \: ( {40})^{2} \\ \\ \\\longrightarrow \sf \: 40 \times 40 = 1600 {cm}^{2}$

now, we have to find total paper required for box

$\longrightarrow \sf \: no \: of \: sq \: paper \: required \: = \frac{tsa \: of \: cuboid}{area \: of \: sq \: paper} \\ \\ \\ \longrightarrow \sf \cancel \frac{11200}{1600} \\ \\ \\ \longrightarrow \sf \: 7papers$

∴ 7 papers are required.