SOLUTION: the radius of a cylinder is increased by 15% and its height is decreased by 20%. Find the percentage change in the volume of the cylinder.

Question 903866: the radius of a cylinder is increased by 15% and its height is decreased by 20%. Find the percentage change in the volume of the cylinder.
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
V cylinder = pi*r^2*h
Volume
V1= pi*r1^2*h1
volume after change in radius and height
V2= pi*r2^2*h2
r2= 1+15/100 = 1+.15=1.15r1

h2= 1-20/100 = 1-0.2 = 0.8h1
V2= pi*(1.15r1)^2*(0.8h1)
=pi*1.32r1^2*0.8h1
=1.06pir1^2h1^2
Increase in volume = 1.06pir1^2h1^2-pir1^2h1^2
=0.06pir1^2h1^2
increase in volume/original volume * 100
(0.06pir1^2h1^2/pir1^2h1^2)*100
=6%

RELATED QUESTIONS
the radius of cylinder is increased by 15% and its height is decreased by 20%. Find the... (answered by Fombitz)

the radius of base of a right circular cylinder is increased by 25% and its height is... (answered by ankor@dixie-net.com)

The radius of a right circular cylinder is increased by 40% and the height is decreased... (answered by Alan3354)

If the radius of a cylinder is decreased by 50% and the height is increased by 50%, then... (answered by Theo)

The radius of a cylinder is increased by 40%, but the height is cut in half. What is the (answered by josgarithmetic,ikleyn)

I need help with this question: If the radius of the base of a cylinder is increased by... (answered by stanbon)

The altitude of the cylinder is increased by 20% while its radius is also increased by... (answered by josgarithmetic)

If the length of a rectangle is increased by 40% and its width is decreased by 20%, what... (answered by checkley77)