Plotting 6 pointed star and hexagon

I have an assignment to plot various figures, I stuck with;

1)a 6 pointed star

I did a 5 pointed star with;
theta=pi/2:4/5*pi:4.8*pi
r=ones(1,6)
polar(theta,r)

I can't get a 6 pointed star to plot correctly

2) a hexagon

thanks