Question

Two cubes, each of volume 64 cm³, are joined end to end. Find the total surface area of the resulting cuboid.

Answer 1

Volume of the cube = a³ 

Therefore,

a³ = 64

⇒ a³ = (4)³

⇒ a = 4

Each side of the cube = 4 cm

Then,

Length of the cuboid = (2 × 4)

Breadth of the cuboid = 4 cm

Height of the cuboid = 4 cm

Total surface area of the cuboid = 2(lb + bh + lh)

= 2[(8 × 4) + (4 × 4) + (8 × 4)] cm²

= (2 × 80) cm² 

= 160 cm²