A cylinder has a height that is 3 times as large as it's radius. The lateral area of the cylinder is 54π square units. What is the length of the cylinder?

Show work.

(This is 10th grade, please don't make it advanced.)

1 answer

Let's start by using the formula for the lateral surface area of a cylinder:

Lateral Surface Area = 2πrh

where r is the radius and h is the height.

We know that the lateral surface area is 54π, so:

54π = 2πr(3r) (since h is 3 times r)

54π = 6πr^2

Divide both sides by 6π:

9 = r^2

Take the square root of both sides:

r = 3

Now that we know the radius is 3 units, we can use the height equation to find the height:

h = 3r = 3(3) = 9

Therefore, the height of the cylinder is 9 units. To find the length (which is the same as the height in this case), we simply double the height:

Length = 2h = 2(9) = 18

So the length of the cylinder is 18 units.