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2cm and 5 cm
Question
Find the surface area of a cylinder with a radius of 4 and a height of 3. Use 3.14 for π
.

Round your answer to the nearest tenths place.

(1 point)
Responses

87.9 cm2
87.9 cm 2

175.8 cm2
175.8 cm 2

120.3 cm2
120.3 cm 2

75.3 cm2

1 answer

To find the surface area of a cylinder, we 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:

  • Radius (\( r \)) = 4 cm
  • Height (\( h \)) = 3 cm

Let's plug the values into the formula:

\[ \text{Surface Area} = 2 \times 3.14 \times 4 \times (3 + 4) \] \[ = 2 \times 3.14 \times 4 \times 7 \] \[ = 2 \times 3.14 \times 28 \] \[ = 6.28 \times 28 \] \[ = 176.84 \]

Now rounding to the nearest tenths place:

\[ 176.84 \approx 176.8 , \text{cm}^2 \]

However, since this value does not match any of the provided responses, let’s double-check through calculating the total surface area of the cylinder, which also involves the areas of the two circular bases.

The total surface area formula also can be split into:

\[ \text{Surface Area} = 2\pi r^2 + 2\pi rh \]

Calculating each part:

  1. Area of the bases: \[ 2\pi r^2 = 2 \times 3.14 \times (4^2) = 2 \times 3.14 \times 16 = 100.48 , \text{cm}^2 \]

  2. Lateral surface area: \[ 2\pi rh = 2 \times 3.14 \times 4 \times 3 = 2 \times 3.14 \times 12 = 75.36 , \text{cm}^2 \]

  3. Total surface area: Combining both parts: \[ 100.48 + 75.36 = 175.84 , \text{cm}^2 \]

Rounding this to the nearest tenths place gives:

\[ 175.8 , \text{cm}^2 \]

So, the correct response is:

175.8 cm²