Question

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

Answer 1

Given, volume of the cube. 

V = a³ = 64 cm³ 

∴ a³ = 4 × 4 × 4 = 4³, 

Hence a = 4 cm 

When two cubes are added, the length of cuboid 

= 2a = 2 × 4 = 8 cm,

breadth = a = 4 cm. 

height = a = 4 cm is formed.

∴ T.S.A. of the cuboid 

= 2 (lb + bh + lh) 

= 2(8 × 4 + 4 × 4 + 8 × 4) 

= 2(32 + 16 + 32) 

= 2 × 80 

= 160 cm² 

∴ The surface area of resulting cuboid is 160 cm².