An easy solution of a problem, in which a circle is searched for, given three circles tangent to it
Euler gives us three points, A, B, and C, the distances between them, and that they are centers of circles of radius a, b, and c respectively. He finds a point O, the center of a circle, and the radius x of that circle, such that the circle is tangent to each of the three given circles.
Original Source Citation
Nova Acta Academiae Scientiarum Imperialis Petropolitanae, Volume 6, pp. 95-101.
Opera Omnia Citation
Series 1, Volume 26, pp.270-275.