Posted by Mike on Friday, May 16, 2008 at 9:57pm.
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

Math  Reiny, Friday, May 16, 2008 at 11:12pm
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