A certain right circular cylinder has a radius of 5 inches. There is a kind of liquid filled in this cylinder to the height of 9 inches. If this liquid is poured completely into a second right cylinder, then the liquid will fill the second cylinder to the height of 4 inches. What is the radius of the second cylinder, in inches?
A. 6
B. 6.5
C. 7
D. 7.5
E. 8
(D)
What was your thinking for logic?
Cylinder - Geometry
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- ssmiles08
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you can find the solution by a straight plug in of the formula.
Volume of cylinder = 2*pi*r^2*h
assume, the liquid is filled to the capacity for both cylinders.
V of 1st cylinder = 450*pi
V of 2nd cylinder = 2*pi*r^2*4
450*pi = 8*pi*r^2
225/4 = r^2
sqrt both sides = 15/2 ~ 7.5 (D)
Volume of cylinder = 2*pi*r^2*h
assume, the liquid is filled to the capacity for both cylinders.
V of 1st cylinder = 450*pi
V of 2nd cylinder = 2*pi*r^2*4
450*pi = 8*pi*r^2
225/4 = r^2
sqrt both sides = 15/2 ~ 7.5 (D)
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Area of cylinder = pi*r^2*h = pi*r1^2*h1doclkk wrote:A certain right circular cylinder has a radius of 5 inches. There is a kind of liquid filled in this cylinder to the height of 9 inches. If this liquid is poured completely into a second right cylinder, then the liquid will fill the second cylinder to the height of 4 inches. What is the radius of the second cylinder, in inches?
A. 6
B. 6.5
C. 7
D. 7.5
E. 8
=> r1 = r*sq(h/h1)
=> r1 = 5*sq(9/4) = 5*3/2 = 7.5
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- Jeff@TargetTestPrep
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Let's find the volume of the liquid in the first cylinder:doclkk wrote:A certain right circular cylinder has a radius of 5 inches. There is a kind of liquid filled in this cylinder to the height of 9 inches. If this liquid is poured completely into a second right cylinder, then the liquid will fill the second cylinder to the height of 4 inches. What is the radius of the second cylinder, in inches?
A. 6
B. 6.5
C. 7
D. 7.5
E. 8
V = πr^2 * h = π(5)^2 * 9 = 225π cubic inches
Now we can let x = radius of the second cylinder and solve for x by setting the volume of the liquid in the second cylinder equal to 225Ï€:
Ï€x^2 * 4 = 225Ï€
x^2 * 4 = 225
x^2 = 225/4
x = √(225/4)
x = 15/2
x = 7.5
Answer: D
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