This is the step-by-step, printable version. If you PRINT this page, any ads will not be printed.
See also the animated version.
|After doing this
|Your work should look like this
We start with a triangle ABC.
|1. Find the bisector of one of the triangle sides. Any one will do. See Constructing the Perpendicular Bisector of a Line Segment.
|2. Repeat for the another side. Any one will do.
|Optional step. Repeat for the third side. This will convince you that the three bisectors do, in fact, intersect at a single point. But two are enough to find that point.
|3. The point where these two perpendiculars intersect is the triangle's circumcenter, the center of the circle we desire. Note: This point may lie outside the triangle. This is normal.
|4. Place the compasses' point on the intersection of the perpendiculars and set the compasses' width to one of the points A,B or C. Draw a circle that will pass through all three.
|5. Done. The circle drawn is the triangle's circumcircle, the only circle that will pass through all three of its vertices.