Question

The edges of three cubes are3cm,4cm and 5cm. The cubes are melted and recast into a single cube. Find the length of a diagonal of the cube.

Answer 1

sum of the volumes of all the cubes is
3³+4³+5³=27+64+125=216cm³
so
volume of the new cube is 216cm³
now side =³√216
i. e is 6cm
diagonal is =s*√3
6*1.732
that is4. 268 or 4.27cm