A cylinder has a radius of 4 cm and a height of 10 cm. What is the surface area of the cylinder? Hint: Use the formula for the surface area of a cylinder: SA= 2 π r2 + 2 π r h Use 3.14 for π.

1 answer

To calculate the surface area (SA) of the cylinder, you can use the formula:

\[ SA = 2\pi r^2 + 2\pi rh \]

Given:

  • Radius \( r = 4 \) cm
  • Height \( h = 10 \) cm
  • Use \( \pi \approx 3.14 \)

Now, let's calculate each part of the formula.

  1. Calculate the area of the two circular bases \( 2\pi r^2 \): \[ 2\pi r^2 = 2 \times 3.14 \times (4)^2 \] \[ = 2 \times 3.14 \times 16 \] \[ = 2 \times 50.24 \] \[ = 100.48 \text{ cm}^2 \]

  2. Calculate the area of the curved surface \( 2\pi rh \): \[ 2\pi rh = 2 \times 3.14 \times 4 \times 10 \] \[ = 2 \times 3.14 \times 40 \] \[ = 2 \times 125.6 \] \[ = 251.2 \text{ cm}^2 \]

  3. Add the two areas together to get the total surface area: \[ SA = 100.48 + 251.2 \] \[ = 351.68 \text{ cm}^2 \]

Thus, the surface area of the cylinder is \( \approx 351.68 \) cm².