Question

21. A metal sheet 27 cm long, 8 cm broad and 1 cm thick is melted into
a cube. The side of the cube is
(a) 6 cm
(b) 8 cm
(c) 12 cm
(d) 24 cm
​

Answer 1

Volume of sheet = volume of cube

First we will calculate volume of metal sheet =l X b x h

= 27 x8 x1=216cm^3

So volume of the cube is also 216 cm^3

216=a^3

a=cube root of 216= 6

So surface area of sheet = 2(lb+bh+hl)

=2(27x8+8x1+1x27)

=502cm^2

And surface area of cube

=6a^2

=6 x6^2=216cm^2

Difference between surface area = 502-216=286cm^2

Answer 2

Answer:

6 cm

Step-by-step explanation:

Volume of metal sheet = 27cm×8cm×1cm = $216cm^{3}$

to make this a cube all sides have to be equal

if the volume is the same then 1 side = $\sqrt[3]{216}$

because if one side is x then xcm × xcm × xcm = $216cm^{3}$

and x =  $\sqrt[3]{216}$

= 6 cm