Abstract
It is proven that a bijection from the Euclidean plane to itself which preserves triangles of inradius 1 or which preserves triangles of circumradius 1 must be a Euclidean motion.
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References
Beckman, F. S., Quarles, D. A., Jr.: On isometries of Euclidean spaces. Proc. Amer. Math. Soc.4, 810–815 (1953).
Coxeter, H. S. M.: Introduction to Geometry. New York: Wiley. 1961.
Lester, J. A.: Euclidean plane point-transformations preserving unit area or unit perimeter. Archiv Math.45, 561–564 (1985).
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Lester, J.A. A characterization of motions as bijections preserving inradius or circumradius one. Monatshefte für Mathematik 101, 151–158 (1986). https://doi.org/10.1007/BF01298927
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DOI: https://doi.org/10.1007/BF01298927