Question

The area of four walls of a room to be painted of sides 3cm, 5cm and 7cm is

a) 142cm2

b) 105cm2 c) 112 cm2

d) 30 cm2​

Answer 1

$\huge{ \mathfrak{ \color{navy}{Question:- }}}$

• The area of four walls of a room to be painted of sides 3cm, 5cm and 7cm is

a) 142cm²

b) 105cm²

c) 112 cm²

d) 30 cm2²

$\huge{ \color{green}{ \mathfrak{Given:-}}}$

• Length =3 cm
• Breadth = 5cm
• Height = 7cm

$\huge{ \mathfrak{ \color{pink}{To \: find:-}}}$

• The area of four walls of a room to be painted

$\huge{ \mathfrak{ \color{brown}{Answer:-}}}$

• $\large \sf \: 112m²$

$\huge{ \mathfrak{ \color{gold}{Step \: by \: step \: Solution:- }}}$

$\\ \: \: \: \: \: \: \: \: \: \: \implies \: \boxed{ \underline{ \sf{ \red{Area \: of \: four \: walls = 2h(l + b)}}}}$

$\\ \: \: \: \: \: \: \: \implies{ \boxed{ \sf 2 \times 7(3 + 5)}} {m}^{2}$

$\\ \: \: \: \: \: \: \: \red \longmapsto \: 14 \times 8 {m}^{2}$

$\\ \: \: \: \: \: \: \: \: \pink \longmapsto \: 112 {m}^{2}$

$\boxed{ \underline{ \sf{ \pink{Therefore \: the \: area \: of \: four \: walls \: of \: a \: room \: to \: be \: painted \: is \:{ \boxed{ \red{ \mathfrak{112m²}}}}}}}}$

${ \blue{━━━━━━━━━━━━━━━━━━━━━━━━━━━━━}}$

Answer 2

Answer :

• Area of four walls of a room to be painted is 112cm²
• (c) Option

Given :

• The area of four walls of a room to be painted of sides 3cm , 5cm and 7cm

To find :

• Area of four walls of a room to be painted

Solution :

Given ,

• Length = 3cm
• Breadth = 5cm
• Height = 7cm

So , room is like a cuboid then ,

As we know that,

• Lateral surface area of cuboid = 2h(l + b)

where, l is length 3cm , b is breadth 5cm and h is height 7cm

》 2h(l + b)

》2 × 7 (3 + 5)

》14(8)

》112cm²

Hence , Area of four walls of a room to be painted is 112cm²

More Explanation:

• Volume of cuboid = lbh
• Total surface area of cuboid = 2(lb + bh + lh)
• Perimeter of cuboid = 4(l + b + h)
• where, l is length , b is breadth and h is height