SOLUTION: The radius of a cylinder is increased by 40%, but the height is cut in half.
What is the resulting change in volume?
A.2% decrease B. 30% decrease C. 30% increase D. 2% increas
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-> SOLUTION: The radius of a cylinder is increased by 40%, but the height is cut in half.
What is the resulting change in volume?
A.2% decrease B. 30% decrease C. 30% increase D. 2% increas
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Question 284724: The radius of a cylinder is increased by 40%, but the height is cut in half.
What is the resulting change in volume?
A.2% decrease B. 30% decrease C. 30% increase D. 2% increase
You can put this solution on YOUR website! let r be the radius
h the height
volume of cylinder = pi*r^2*h
r is increased by 40 %
new radius = 1.4
new height = 0.5h
new volume = pi*(1.4r)^2 * 0.5h
original volume / new volume = pi*r^2*h / pi* (1.4r)^2*0.5h
= 1/(1.4)^2*0.5)
=1.02
meaning 2 % increase
You can put this solution on YOUR website! The radius of a cylinder is increased by 40%, but the height is cut in half.
What is the resulting change in volume?
A.2% decrease B. 30% decrease C. 30% increase D. 2% increase
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The radius is multiplied by 1.4. The radius in the formula is squared, so the volume is multiplied by 1.4^2 = 1.96
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The height is multiplied by 0.5, and it's to the first power, so the volume is directly related to h.
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Volume is multiplied by 1.96*0.5 = 0.98
That's a 2% reduction
A
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Another tutor got the same numbers, but used the "after" volume as a reference. The original volume should be used as the reference.
