Question

Two identical solid cubes of side a are joined end to end. The total surface area of the resulting cuboid is _________.

Answer 1

Length of the resulting cuboid, l = a + a = 2a

Breadth of the resulting cuboid, b = a

Height of the resulting cuboid, h = a

∴ Total surface area of the resulting cuboid

= 2(lb + bh + hl)

= 2(2a × a + a × a + a × 2a)

= 2(2a² + a² + 2a²)

= 2 × 5a²

= 10a²

Two identical solid cubes of side a are joined end to end. The total surface area of the resulting cuboid is ____10a²_____.