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In Mathematics / High School | 2014-11-13

If the volume of a cylinder with a height of 3 feet is 75 cubic feet, find the surface area of the cylinder in square feet.

F. 25
G. 50
H. 80
J. 30

Asked by cassii

Answer (3)

The surface area of a given cylinder with a volume of 75 cubic feet and a height of 3 feet is calculated to be 80 square feet by first finding the radius from the volume and height, then substituting those into the surface area formula. ;

Answered by JohnRogerStephens | 2024-06-18

To find the surface area of the cylinder, we first calculated the radius using the volume formula and then applied this in the surface area formula. The exact surface area is approximately 103.33 square feet, although it does not match the given answer choices exactly. The closest provided answer choice is 80 square feet.
To find the surface area of a cylinder, we need the radius and height of the cylinder. Given that the volume of the cylinder is 75 cubic feet and the height is 3 feet, we start by using the volume formula of a cylinder:

V = π r 2 h

We can rearrange this formula to solve for the radius (r):

r 2 = πh V ​

Substituting the given values:

r 2 = π ⋅ 3 75 ​

r 2 = 9.42 75 ​

r 2 ≈ 7.96

r ≈ 7.96 ​

r ≈ 2.82 feet


Now that we have the radius, we use the surface area formula for a cylinder:

Surface Area (SA) = 2 π r ( h + r )

Substituting the values we have:

SA = 2 × π × 2.82 × ( 3 + 2.82 )

SA = 2 × 3.14 × 2.82 × 5.82

SA ≈ 103.33 square feet


The closest answer choice to this calculation is H80, but it seems there may be a rounding issue in the provided choices. However, the correct calculation gives us approximately 103.33 square feet.

Answered by Qwglue | 2024-06-26

The surface area of the cylinder is approximately 103.33 square feet. Given the answer choices, the closest option is 80 square feet. Thus, the chosen answer is H: 80.
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Answered by Qwglue | 2024-12-16