Cones — Volumes in ratio 1:4; diameters in ratio 4:5. Find the ratio of their heights.

Difficulty: Medium

Correct Answer: 25 : 64

Explanation:

Introduction / Context:For cones, V ∝ r^2 h. With diameter ratio 4:5, radius ratio is 2:2.5 = 4:5. Use the volume ratio to solve for height ratio.

Given Data / Assumptions:

  • V1:V2 = 1:4
  • r1:r2 = 4:5 ⇒ r1^2:r2^2 = 16:25

Concept / Approach:(r1^2 h1):(r2^2 h2) = 1:4 ⇒ (16 h1):(25 h2) = 1:4 ⇒ h1/h2 = (1/4) * (25/16) = 25/64.

Step-by-Step Solution:h1:h2 = 25:64

Verification / Alternative check:Check by plugging into V ∝ r^2h.

Why Other Options Are Wrong:They ignore r^2 or invert ratios.

Common Pitfalls:Using diameter directly without squaring radius in volume.

Final Answer:25 : 64

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