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We start with three given points. We will construct a circle that passes through all three.
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1. (Optional*) Draw straight lines to create the line segments AB and BC.
Any two pairs of the points will work.
* We draw the two lines to make it clear when we later draw their perpendicular bisectors,
but it is not strictly necessary for them to actually be there to do this.
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| 2. Find the perpendicular bisector
of one of the lines. See
Constructing the Perpendicular Bisector of a Line Segment. |
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| 3. Repeat for the other line. |
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| 4. The point where these two perpendiculars intersect is the center of the circle we desire. |
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| 5. Place the compass point on the intersection of the perpendiculars and set the compass width to
one of the points A,B or C. Draw a circle that will pass through all three. |
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| 6. Done. The circle drawn is the only circle that will pass through all three points. |
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