Question

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A cone with a diameter of 8 inches and a height of 7 inches.


Find the surface area of the cone. Use 3.14 for

π

.

Answer 1

138.16 in²

Explanation:

The surface area SA of the cone is the sum of the base area B and the lateral area LA. The lateral area is half the product of the circumference and the slant height. The radius is half the diameter, so is 4 inches.

SA = B + LA

= πr² + (1/2)(2πrh) . . . . where h is the slant height

= (πr)(r +h)

Filling in the numbers, you have ...

SA = (3.14)(4 in)(4 in + 7 in) = 3.14×(44 in²) = 138.16 in²