Question

Three cubes of sides 8 cm, 6 cm and 1 cm are
melted to form a new cube. The surface area
of the cube so formed is:​

Answer 1

Volume of cube:-

1) with side 8 cm = 8³ cubic cm = 512 cubic cm.

2) with side 6 cm = 6³ cubic cm = 216 cubic cm.

3) with side 1 cm = 1³ cubic cm = 1 cubic cm

∴ Volume of the new cube formed by melting the three cubes = (512+216+1) cubic cm = 729 cubic cm.

∴ Side of the new cube = ³√729 cm = 9 cm

∴ Surface Area of the new cube = {6×(9²)} square cm

= (6×81) square cm

= 486 square cm