Correct Answer - Option 1 : 180 cm

**Given**

Lateral surface area = 900 sq.cm

**Formula used **

Lateral surface area = 4(side)^{2}

Sum of all edges = 12 × side [As there are 12 edges of a cube]

**Calculation**

Lateral surface area = 900

4(side)^{2} = 900

⇒ (Side)^{2} = 225

⇒ (Side) = 15

Total rope required to cover all edges = 15 × 12

⇒ 180 cm

**∴ Total length of rope required is 180 cm**