I've a question for you

If I would create the Mercedes logo (the famous 3 points star), could you explain to me how can I realize the 3 points of the star respecting perfectly the distances between each point?
I know that I have to
- create a point of the star;
- clone it applying a rotation of 120 degrees...
..but I can't do the second point

please, heeelp!
Thanks all and sorry for my bad english!