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## Homework Statement

Determine the surface area and volume of a solid formed by rotating an equilateral triangle of side a about its base.

## Homework Equations

## The Attempt at a Solution

----------working out surface area--------

Integral of 2.pi.y dx with limits of a and 0.

I worked out; y = root3 . x

therefore surface area = root3.pi.a^2.

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---------volume of revolution---------------

integral of pi.y^2. dx with limits of a and 0.

y = root3.x

therefore volume of solid formed = pi.a^3

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I hope someone can check my answer to the first part (working out surface area) and then tell me where i went wrong with the volume of revolution.

The answer for the second part (volume of revolution) should be (pi.a^3)/4

Thanks.