Question

a solid cube of side 12cm is cut into eight cubes of equal volume.what will be the side of the new cube?also ,find the ratio between their csa ? please help 9 class question

Answer 1

Side (a) of cube = 12 cm

Volume of cube = (a)3 = (12 cm)3 = 1728 cm3

Let the side of the smaller cube be a1.

Volume of 1 smaller cube 

⇒ a1 = 6 cm

Therefore, the side of the smaller cubes will be 6 cm.

Ratio between surface areas of cubes

Therefore, the ratio between the surface areas of these cubes is 4:1.

Answer 2

side of cube=12cm

volume=side^3

=12×12×12

=1728cm^3

if it's divided into 8 smaller cubes then the volume of the small cubes will be=1728/8

=216cm^3

therefore side of the smaller cube=side^3

side^3=216

side=6cm

CSA of big cube=6a^2

=6×12^2

=6×144

=864cm^2

CSA of smaller cube=6a^2

=6×6^2

=6×36

=216cm^2

ratio:-

864:216

4:1

hope this helps...