Hello I have a question regarding first practice question: 1) How did we know origin was (0,0) of circle? 2) I understand the radius’ will change as x and y change, but for each radius to give us a concentric circle, the theta needs to change right? But why would the theta be changing? 3) These circles are hollow correct? Since we just are using the end point of the radius for each point so a circle is traced by the end of just the one point at end of radius right? Thank you Dr!