Why does integrating perimeter not give area of equilateral triangle?

171 Views Asked by At

I want to derive the formula for the area of an equilateral triangle by integrating a simple formula for its perimeter. Here's my attempt that doesn't work.

I want to know why it doesn't work.

3 * side = perimeter

area = integral of perimeter wrt side

area = 3/2 * side^2

But I know that the real formula is area = (sqrt(3)/4) * s^2.

So what's wrong with the way I'm trying to get the formula?

Cheers