how to find the distance between two points in the polar coordinate system?

Question

Help me, please! how to find the distance between two points $ A( x_1,y_1 )$ $ B( x_2,y_2 )$ in the polar coordinate system?

Answer 1

For points $A(x_1,y_1)$, $B(x_2,y_2)$ where $$x_1=r_1cos\theta_1$$ $$y_1=r_1sin\theta_1$$ $$x_2=r_2cos\theta_2$$ $$y_2=r_2sin\theta_2$$

The distance then is $$\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$$