A cone shows a radius of 6 and hypotenuse or side as 11.

What is the surface area of the cone? Use 3.14 for pi and round to the nearest tenth, if necessary.

(1 point)

1 answer

To find the surface area of a cone, we need to calculate the lateral surface area and the base area. The formula for the surface area \( S \) of a cone is given by:

\[ S = \pi r l + \pi r^2 \]

where:

  • \( r \) is the radius of the base,
  • \( l \) is the slant height (hypotenuse).

Given:

  • Radius \( r = 6 \)
  • Slant height \( l = 11 \)

Now, we can calculate the surface area as follows:

  1. Calculate the lateral surface area:

\[ \text{Lateral Surface Area} = \pi r l = 3.14 \times 6 \times 11 \]

Calculating this:

\[ = 3.14 \times 6 = 18.84 \] \[ 18.84 \times 11 = 207.24 \]

  1. Calculate the base area:

\[ \text{Base Area} = \pi r^2 = 3.14 \times 6^2 = 3.14 \times 36 \]

Calculating this:

\[ = 3.14 \times 36 = 113.04 \]

  1. Now, combine both areas to find the total surface area:

\[ S = 207.24 + 113.04 = 320.28 \]

Finally, rounding to the nearest tenth:

\[ S \approx 320.3 \]

Therefore, the surface area of the cone is 320.3 square units.