Correct Answer - Option 4 : 4.2 m

**Given**

Height of cone = 100 cm

Volume of sand = 18.48 m^{3}

**Formula used**

Volume of cone = (1/3)πr^{2}h

Where r and h are radius and height of cone respectively

Height = 100 cm or 1 m

**Calculation**

18.48 = (1/3) × (22/7) × r^{2} × 1

⇒ √(18.48 × 7 × 3)/(22) = r

⇒ 4.2 m = r

**∴ Radius of heap of sand is 4.2 m**