After melting three cubes of sides 6 cm, 8 cm and 10 cm, a big cube is made. Find the side of the new cube.

12 cm

We know that,

Volume of a cube = Side³

Let the edge of new cube = a cm.

We also know that,

Volume of the new cube = Sum of the volumes of all the three smaller cubes 

= a³ = 6³ + 8³ + 10³

= a³ = 216 + 512 + 1000 

= a³ = 1728

= a = 12 cm