Three metal cubes whose edges measure `3c m ,\ 4c m\ a n d\ 5c m` respectively are melted to form a single cube. Find its edge. Also, find the surface area of the new cube.

Explanation

Answer:
Let `x cm` be the edge of the new cube.

Then, the volume of the new cube= Sum of the volumes of three cubes
`=>x^3=3^3+4^3+5^3=216`
`=>x^3 = 6^3`
`=>x=6cm`
The edge of the new cube is `6cm` long.
Surface area of the new cube`=6 xx 6^2=6×6^2cm^2=216cm^2`
Hence the answer is `216cm^2`.