| 释义 |
ExradiusThe Radius of an Excircle. Let a Triangle have exradius  (sometimes denoted  ),opposite side  and angle  , Area  , and Semiperimeter  . Then
(Johnson 1929, p. 189), where  is the Circumradius. Let  be the Inradius, then
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References
Johnson, R. A. Modern Geometry: An Elementary Treatise on the Geometry of the Triangle and the Circle. Boston, MA: Houghton Mifflin, 1929.Mackay, J. S. ``Formulas Connected with the Radii of the Incircle and Excircles of a Triangle.'' Proc. Edinburgh Math. Soc. 12, 86-105. Mackay, J. S. ``Formulas Connected with the Radii of the Incircle and Excircles of a Triangle.'' Proc. Edinburgh Math. Soc. 13, 103-104. |
