|
We start with a given circle.
|
 |
| 1. Place the right-angle corner of any object at any point on the circle. Any point will do. |
 |
| 2. Make a mark where the two sides of the right-angle cross the circle. |
 |
| 3. Draw a line between these two marks. Because of Thales Theorem, this is a diameter of the circle. |
 |
| 4. Place the right-angle corner of the object at any other point on the circle. Any point will do, but for greatest accuracy,
make it about a quarter the way round the circle from the first point. |
 |
| 5. Make a mark where the two sides of the right-angle cross the circle. |
 |
| 6. Connect these two points with a straight line. This is the second diameter. |
 |
| 7. Done. The point where the two diameters intersect is the center of the circle. |
 |