Question

A cone is 3 cm high and the radius of its base is 7 cm. It is melted and recasted into a cylinder with height 1 cm. Find the radius of the cylinder.
1. 2 cm
2. 3 cm
3. 7 cm
4. 6 cm

Answer 1

Correct Answer - Option 3 : 7 cm

Given:

Height of cone = 3 cm

Radius of cone = 7 cm

Height of cylinder = 1 cm

Formula used:

Volume of cone = (1/3)πr²h

Where, r and h represents radius and height of cone

Calculation:

Volume of cone = (1/3) × (22/7) × 7 × 7 × 3 = 154 cm²

Volume of cone = Volume of cylinder

⇒ 154 = π(radius)²height

⇒ 154 = (22/7) × (radius)² × 1

⇒ Radius = 7 cm