Step 1. Divide the diameter AX of the circumference into the same number of equal parts as the number of sides that the polygon will have (Thales' theorem).
In this case, we are going to draw a nonagon.
Step 2. Use centre point X and radius AX. Draw an arc that
intersects the extension of the horizontal diameter line at V.
Step 3. Draw a straight line that passes through point V and the second division of the diameter (point 2). Where the straight line intersects the circumference, label the intersection point B.
Step 4. Use radius AB. Draw the arcs that identify the vertices of the polygon. Then draw the sides.
