Plane Geometry

find the area and volume of the figure developed by an equilateral triangle with sides s if it is revolved about one of its sides.

Hello.. and good evening.

I would like to know how to solve for the area of the mid-section of this prismatoid. I tried solving for the volume and I got an answer of 375 cu. ft. but according to Kern and Bland's book the real answer is 310 cu.ft. I guess I made a mistake in solving it.

Can I know the complete solution and the illustration of the top view of the prismatoid's mid-section? Thank you very much to whoever will answer my question. It would be a great help for me.

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