Sorry for asking about very beginner question. But I have no idea how to solve it.

I am modeling a round stool look like this.

When I built one of leg, I don't have idea how to copy another one perfectly.

I tried to use mirror modifier. But it can not save the details of connection.

Is there any easy way to duplicate and paste to the correct part? I only can think that delete the stool leg part one by one and paste it 3 times...

Thanks for helping!