If the volume of a right circular cone of height 30 cm is 160π cm³, find the diameter of its base.

Question

Question

This question was previously asked in

RRB NTPC Graduate Level CBT-I Official Paper (Held On: 09 Jun, 2025 Shift 1)

Answer 1

Given:

Volume of cone (V) = 160π cm³

Height (h) = 30 cm

Formula used:

Volume of cone, V = (1/3) × π × r² × h

Where r = radius of the base

Calculation:

160π = (1/3) × π × r² × 30

⇒ 160 = (1/3) × r² × 30

⇒ 160 × 3 = r² × 30

⇒ 480 = r² × 30

⇒ r² = 16

⇒ r = 4 cm

Diameter = 2 × r

⇒ Diameter = 2 × 4 = 8 cm

∴ The correct answer is option (4).

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