Find the surface area of the cone. Give your final answer rounded to the nearest whole number. Use 3.14 for pi.

radius is 11 in. height is 14 in.

1 answer

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

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

where:

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

First, we need to calculate the slant height \( l \) using the Pythagorean theorem. The slant height is the hypotenuse of a right triangle where one leg is the height of the cone and the other leg is the radius.

The formula for the slant height is:

\[ l = \sqrt{r^2 + h^2} \]

Given:

  • \( r = 11 \) in
  • \( h = 14 \) in

Now calculating \( l \):

\[ l = \sqrt{11^2 + 14^2} = \sqrt{121 + 196} = \sqrt{317} \]

Calculating \( \sqrt{317} \):

\[ l \approx 17.78 \text{ in (rounded to two decimal places)} \]

Now we substitute \( r \) and \( l \) into the surface area formula:

\[ \text{Surface Area} = \pi r (r + l) \] \[ = 3.14 \times 11 \times (11 + 17.78) \] \[ = 3.14 \times 11 \times 28.78 \] \[ = 3.14 \times 11 \times 28.78 \approx 3.14 \times 316.58 \approx 995.43 \]

Now, rounding to the nearest whole number, the surface area of the cone is:

\[ \text{Surface Area} \approx 995 \text{ square inches} \]

Thus, the final answer is:

\[ \boxed{995} \]