
06428012
j
2015d.00651
Northshield, Sam
Complex Descartes circle theorem.
Am. Math. Mon. 121, No. 10, 927931 (2014).
2014
Mathematical Association of America (MAA), Washington, DC
EN
G75
Descartes circle theorem
octahedral configuration of spheres
spheres
doi:10.4169/amer.math.monthly.121.10.927
Summary: We present a short proof of the Descartes circle theorem on the ``curvaturecenters'' of four mutually tangent circles. Key to the proof is associating an octahedral configuration of spheres to four mutually tangent circles. We also prove an analog for spheres.