CIRCLE • CIRCLE • CIRCLE
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Three Externally Tangent Circles
Number of solutions: 2
GeoGebra construction
Steps
- We have circles c, d and h, which are all touching externally.
- Find points D, E and F, in which the circles intersect each other.
- Construct 3 hyperbolas, which have their foci in the circles' centers and cross through one of the points D, E and F, which are located on the circles, whose centers are foci of hyperbolas ?
- Find points S, where all three hyperbolas intersect.
- Construct lines p, which intersect with an S point and one of the circles' centers and find points I and N, which are an intersection of a p line and a circle through whose center p crosses.
- Construct circles k, which have their center in point S and also intersect either point I or N.
GeoGebra construction
Steps
- Draw a circle k4 with centre S4 at the point of contact of two circles, which touches the third one.
- Represent the given circles by the circular inversion according to k4, resulting in the parallel lines c´ and d´ and the circle h´
- Draw the h-axis of the resulting parallel lines.
- Construct the circles k5 and k6 tangent to the two parallels and the circle h´
- Represent the resulting circles by circular inversion to obtain the resulting solutions, circles p´ and q´.