Surface Area of Cones Practice
Math 8 Q2 (Pre-Algebra) / Cones, Cylinders, & Spheres
What is the surface area, in square centimeters, of a cone with a diameter of 12 feet and a slant height of 14 feet? Use 3.14 for pi and round to the nearest tenth, if necessary. (1 point)
First, we need to find the radius of the cone. The radius is half the diameter, so it is 12/2 = 6 feet.
Next, we can use the slant height and the radius to find the height of the cone using the Pythagorean theorem. The height is the square root of (the slant height squared minus the radius squared), so it is sqrt(14^2 - 6^2) = sqrt(196 - 36) = sqrt(160) = 12.65 feet.
The surface area of a cone is given by the formula A = πr(r + l), where r is the radius and l is the slant height.
So, plugging in the values, the surface area is A = 3.14 * 6(6 + 14) = 3.14 * 6 * 20 = 376.8 square feet.
Therefore, the surface area of the cone is approximately 376.8 square feet.