Question

5) A frustrum of a cone has the following dimensions: height = 6 in, lower radius = 8 in, upper radius = 4 inches.( Use pi= 3.14)

find each of the following:

5a) Lateral Surface area = _____ square inches

5b) Total Surface area= ______ square inches

5c) Volume = ______ cubic inches

Answer 1

pretend that you started with a large cone of height 12 in, and radius of 8 in.

To create the fulcrum, you cut off the top consisting of a cone of height 6 in and radius of 4 inches.

to find the lateral surface area of the fulcrum, find the lateral area of the large cone and subtract the lateral area of the imaginary cone that was cut off, leaving you with the lateral surface area of the fulcrum. Don't forget to add the area of the circle at the top of the fulcrum

for the total surface I would add the area of the circular base.

For the volume of the fulcrum, follow the same method

vol of fulcrum = vol of large cone - vol of cone cut off