Question

Difficulty: EasyVolume and Surface Area of Solids

The volume of a right circular cylinder is 72π72\pi. If the radius of the base of the cylinder is 33, what is the height of the cylinder?

Answer: 8

Answer

The height of the cylinder is 8.
The volume VV of a right circular cylinder is given by the formula V=πr2hV = \pi r^2 h, where rr is the base radius and hh is the height. By substituting the given volume of 72π72\pi and radius of 33, we obtain the equation 72π=π(3)2h72\pi = \pi (3)^2 h. Simplifying the right side gives 72π=9πh72\pi = 9\pi h. Dividing both sides of the equation by 9π9\pi isolates the height, giving h=8h = 8.

Step-by-Step Solution

1
Use the formula for the volume of a right circular cylinder.
V=πr2hV = \pi r^2 h
This formula relates the volume, radius, and height of a cylinder.
2
Substitute the known values into the volume formula.
72π=π(3)2h72\pi = \pi (3)^2 h
To form an equation with the unknown height.
3
Simplify the squared radius and isolate the variable.
h=8h = 8
Simplifying 323^2 gives 99. Dividing 72π72\pi by 9π9\pi isolates the height.

Key Concept

Solving for an unknown dimension using the volume formula of a cylinder.
Estimated Time:45s
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