Multiple choice

If the radius of the base and the height of a right circular cone are increased by 20 \%, then what is the approximate percentage increase in volume ?

  1. 60

  2. 68

  3. 73

  4. 75
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Volume of cone V = (1/3)πr²h. When r and h increase by 20%, new volume = (1.2)³ × original = 1.728V. Increase = 72.8%. The formula shows volume scales with the product of r² and h, so a 20% increase in both gives a factor of 1.2² × 1.2 = 1.728.

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