Set the r's equal and we have that
2cos θ = 1 divide both sides by 2
cos θ = 1/2
arccos (1/2) = θ
Remember that arccos has a range of [-pi,2, pi/2 ]
Note that this happens at pi/3 and at -pi/3 = 5pi/3 if we are on the interval [0, 2pi ]
So...the intersection points are
(r, θ) = ( 1, pi/3) and (1, 5pi/3 )