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. 2,198 square inches
2. 1,177.5 square inches
3. 785 square inches
4. 471 square inches
The formula for the surface area of a cone is given by πrs + πr^2, where r is the radius and s is the slant height.
Given that the radius is 10 inches and the slant height is 15 inches, we can substitute these values into the formula:
Surface area = π(10)(15) + π(10^2)
= 150π + 100π
= 250π
To find the approximate value, we can substitute 3.14 for π:
Surface area ≈ 250(3.14)
≈ 785 square inches
Therefore, the correct answer is 3. 785 square inches.