Volume of solid of revolution - watermelon

Because the melon is symmetrical, we can work out the volume of one half of the melon, and then double our answer.

The radii for the slices for one half of a particular watermelon are found from measurement to be:

`0, 6.4, 8.7,` `10.3, 11.3,` `12.0, 12.4, 12.5.`

The approximate volume for one half of the melon using slices 2 cm thick would be:

`"V"_[text[half]]=pi times [6.4^2 + 8.7^2+10.3^2+11.3^2+12.0^2+12.4^2+12.5^2] times 2`

`= pi times 8040.44 times 2`


So the volume for the whole watermelon is about

`5054.4 × 2 = 10109\ "cm"^3= 10.1\ "L"`.

In the following question, we see how to find the "exact" value using the volume of solid of revolution formula.

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