Question

Find the surface area of a cylinder with a radius of 4 cm and a height of 9 cm. Use 3.14 for π

904.32 cm2

326.56 cm2

251.2 cm2

276.32 cm2

Answer 1

To find the surface area of a cylinder, you can use the formula:

\[
\text{Surface Area} = 2\pi r(h + r)
\]

where:
- \( r \) is the radius,
- \( h \) is the height,
- \( \pi \) is approximately \( 3.14 \).

Given:
- \( r = 4 \) cm
- \( h = 9 \) cm

Now, plug the values into the formula:

\[
\text{Surface Area} = 2 \times 3.14 \times 4 \times (9 + 4)
\]

Calculating the height plus radius:

\[
9 + 4 = 13
\]

Now replace back into the formula:

\[
\text{Surface Area} = 2 \times 3.14 \times 4 \times 13
\]

Calculating step-by-step:

1. Calculate \( 2 \times 3.14 \):
\[
2 \times 3.14 = 6.28
\]

2. Now, calculate \( 6.28 \times 4 \):
\[
6.28 \times 4 = 25.12
\]

3. Finally, multiply by 13:
\[
25.12 \times 13 = 326.56
\]

Therefore, the surface area of the cylinder is:

\[
\text{Surface Area} = 326.56 \, \text{cm}^2
\]

Thus, the correct answer is:

**326.56 cm²**