| Description | Line passing through the pole making an angle \(\alpha\) with the polar axis | Vertical line | Horizontal line |
| Rectangular equation | \(y=(\tan \alpha)x\) | \(x=a\) | \(y=b\) |
| Polar equation | \(\theta = \alpha\) | \(r \cos \theta = a\) | \(r \sin \theta =b\) |
| Typical graph |  |  |  |
| Description | Circle, center at the pole, radius \(a\) | Circle, passing through the pole, tangent to the line \(\theta=\dfrac{\pi}{2}\), center on the polar axis, radius \(a\) | Circle, passing through the pole, tangent to the polar axis, center on the line \(\theta = \dfrac{\pi}{2}\), radius \(a\) |
| Rectangular equation | \(x^2+y^2=a^2,\;a>0\) | \(x^2+y^2=\pm 2ax,\;a>0\) | \(x^2+y^2=\pm 2ay,\;a>0\) |
| Polar equation | \(r=a,\;a>0\) | \(r=\pm 2a \cos\theta,\;a>0\) | \(r=\pm 2a \sin\theta,\;a>0\) |
| Typical graph |  |  |  |