Question

Question
A water tank is in the shape of a right circular cylinder. The diameter is 8 feet, and the height is 21.5
feet. Find the surface area of the water tank. Use 3.14
for π
. Express your answer in decimal form.(1 point)

Answer 1

To find the surface area of a right circular cylinder, we use the formula:

\[
SA = 2\pi r(h + r)
\]

where \( r \) is the radius and \( h \) is the height of the cylinder.

1. **Find the radius**:
The diameter of the cylinder is 8 feet, so the radius \( r \) is half of the diameter:
\[
r = \frac{8}{2} = 4 \text{ feet}
\]

2. **Substitute the values into the surface area formula**:
Given that \( h = 21.5 \) feet and using \( \pi \approx 3.14 \):
\[
SA = 2 \times 3.14 \times 4 \times (21.5 + 4)
\]

3. **Calculate \( h + r \)**:
\[
h + r = 21.5 + 4 = 25.5
\]

4. **Calculate the surface area**:
Now plug this value back into the surface area formula:
\[
SA = 2 \times 3.14 \times 4 \times 25.5
\]

First, calculate \( 2 \times 3.14 \times 4 \):
\[
2 \times 3.14 = 6.28
\]
\[
6.28 \times 4 = 25.12
\]

Now multiply by \( 25.5 \):
\[
SA = 25.12 \times 25.5
\]

Calculate \( 25.12 \times 25.5 \):
\[
SA \approx 640.56
\]

Thus, the surface area of the water tank is approximately \( 640.56 \) square feet.