Question

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

Answer 1

Volumebof 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