Question

The radius AND height of a cone are each doubled. What is the new volume? A) 4 3 πhr2 B) 8 3 πhr2 C) 4πhr2 D) 8πhr2

Answer 1

Answer: B

Step-by-step explanation:

Answer 2

Volume of cone:
$V = \dfrac{1}{3}\pi r^2h$

Double the radius to 2r, and double the height to 2h.
Volume of new larger cone:
$V = \dfrac{1}{3}\pi(2r)^2 \times 2h$

$V = \dfrac{1}{3}\pi \times 4r^2 \times 2h$

$V = \dfrac{1}{3}\pi \times 8r^2 h$

$V = \dfrac{8}{3}\pi r^2 h$

Answer: Choice B)