释义 |
Brocard AngleDefine the first Brocard Point as the interior point of a Triangle for which theAngles , , and are equal. Similarly, define the secondBrocard Point as the interior point for which the Angles , , and are equal. Then the Angles in both cases are equal, and this angle iscalled the Brocard angle, denoted .
The Brocard angle of a Triangle is given by the formulas
 |  |  | (1) | |  |  | (2) | |  |  | (3) | |  |  | (4) | |  |  | (5) |  |  |  | (6) |  |  |  | (7) |
where is the Triangle Area, , , and are Angles, and , , and are sidelengths.
If an Angle of a Triangle is given, the maximum possible Brocard angle is given by
 | (8) |
Let a Triangle have Angles , , and . Then
 | (9) |
where
 | (10) |
(Le Lionnais 1983). This can be used to prove that
 | (11) |
(Abi-Khuzam 1974).See also Brocard Circle, Brocard Line, Equi-Brocard Center, Fermat Point, Isogonic Centers References
Abi-Khuzam, F. ``Proof of Yff's Conjecture on the Brocard Angle of a Triangle.'' Elem. Math. 29, 141-142, 1974.Johnson, R. A. Modern Geometry: An Elementary Treatise on the Geometry of the Triangle and the Circle. Boston, MA: Houghton Mifflin, pp. 263-286 and 289-294, 1929. Le Lionnais, F. Les nombres remarquables. Paris: Hermann, p. 28, 1983.
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