SOLUTION: the external dimension of a closed cylindrical watertank made of concrete materials consist of its radius which is 3 meters and height is 8 meters.if the thinkness of the concrete

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Question 1002230: the external dimension of a closed cylindrical watertank made of concrete materials consist of its radius which is 3 meters and height is 8 meters.if the thinkness of the concrete walls is 1 decimeter,find the volume of the concrete walls to the nearest m
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Internal radius, being 1%2F10 meter less than the external, is 3-1%2F10. The internal height, which points in two directions, maybe up and down, is 8-2%281%2F10%29. A little more simply, height internally is 8-1%2F5.

Volume of the concrete walls, total volume minus the internal volume:
pi%2A8%2A3%5E2-pi%2A%288-1%2F5%29%2A%283-1%2F10%29%5E2
That is the basic beginning, just so you can see and understand.

pi%2A8%2A9-pi%2A%2839%2F5%29%2829%2F10%29%5E2

pi%2872-%2839%2F5%29%2829%2F10%29%5E2%29

highlight%286.402%2Api%29, cubic meters