Sometimes in a drawing or painting you need to find the center of a circle. This technique is mathematically correct, but as an artist I just eyeball the distances.
Keep on practicing and you will manage it real quick.

  • Get your circle
  • Draw at least three lines intersecting the circle.
  • Find the halfway point of those lines.
  • Draw a 90 degree line from that halfway-point.
  • The middle of the circle is where those lines intersect.