Difficulty: Easy
Correct Answer: 49 π √32/3 m3
Explanation:
Introduction / Context:
To compute a cone’s volume when radius and slant height are given, first find the vertical height using Pythagoras on the right triangle formed by radius, height, and slant height. Then apply the standard cone volume formula.
Given Data / Assumptions:
Concept / Approach:
Compute h = sqrt(l^2 − r^2). Then volume V = (1/3)π r^2 h. Leave the radical in simplest exact form for a clean expression.
Step-by-Step Solution:
h = sqrt(9^2 − 7^2) = sqrt(81 − 49) = sqrt(32)V = (1/3)π * 7^2 * sqrt(32) = (1/3)π * 49 * sqrt(32)Therefore, V = 49 π √32 / 3 m3
Verification / Alternative check:
Approximate: √32 ≈ 5.657; V ≈ (49 * 5.657 / 3)π ≈ (277.2/3)π ≈ 92.4π m3, consistent.
Why Other Options Are Wrong:
All other forms mis-handle constants or the radical; the correct combination of r^2 and √32 is specific.
Common Pitfalls:
Using l in place of h in the volume formula; forgetting to square the radius.
Final Answer:
49 π √32/3 m3
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