Let the edge of new cube be a cm.
The sides of the three cubes are 8 cm, 6 cm and 1 cm.
It is given that, the three cubes are melted to form the new cube.
∴ Volume of the new cube = Sum of volumes of the three cubes
⇒ a3 = (8 cm)3 + (6 cm)3 + (1 cm)3 [Volume of cube = (Side)3]
⇒ a3 = 512 + 216 + 1 = 729 cm3
⇒ a3 = (9 cm)3
⇒ a = 9 cm
∴ Surface area of the new cube = 6a2 = 6 × (9 cm)2 = 6 × 81 cm2 = 486 cm2
Thus, the surface area of the new cube is 486 cm2.
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 ___486 cm2____.