What is the surface area, in square inches, of a cone with a radius of 10 inches and a slant height of 15 inches? Use 3.14 for pi.(1 point) Responses 785 square inches 785 square inches 2,198 square inches 2,198 square inches 471 square inches 471 square inches 1,177.5 square inches

1 answer

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

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

where:

  • \( r \) is the radius of the base,
  • \( l \) is the slant height,
  • \( \pi \) is approximately 3.14.

Given:

  • \( r = 10 \) inches,
  • \( l = 15 \) inches.

Let's calculate each part.

  1. Calculate the area of the base:

\[ \text{Base Area} = \pi r^2 = 3.14 \times (10)^2 = 3.14 \times 100 = 314 \text{ square inches} \]

  1. Calculate the lateral surface area:

\[ \text{Lateral Surface Area} = \pi r l = 3.14 \times 10 \times 15 = 3.14 \times 150 = 471 \text{ square inches} \]

  1. Now, add both areas to get the total surface area:

\[ \text{Total Surface Area} = \text{Base Area} + \text{Lateral Surface Area} = 314 + 471 = 785 \text{ square inches} \]

Therefore, the surface area of the cone is 785 square inches.