
Hello,
I am not entirely sure how to do this question, as I understand a rotation in the complex plane can be described by using Euler's formula, $e^{i\theta}$. Since this is an equilateral triangle theta is $\pi/6$ but I don't know where to go from this?
Any help will be appreciated, thanks.
Hint:
I f a vertex of the triangle is represented by the complex number $a$, the other vertex are obtained from $a$ by rotations , about the origin, of angles $2\pi/3$ and $4\pi/3$. So they are: $b=a e^{2i\pi/3}$ and $c=a e^{4i\pi/3}$.
Use this in your formula and you can verify the result.