For two lines in the plane with endpoints and , the angle between them is given by

(1)

The angle
between two lines in the plane specified in trilinear
coordinates by
is given by

(4)

where

(5)


(6)

(Kimberling 1998, p. 31).
See also
LineLine Distance,
LineLine
Intersection,
Trilinear Line
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References
Kimberling, C. "Triangle Centers and Central Triangles." Congr. Numer. 129, 1295, 1998.Referenced on WolframAlpha
LineLine Angle
Cite this as:
Weisstein, Eric W. "LineLine Angle."
From MathWorldA Wolfram Web Resource. https://mathworld.wolfram.com/LineLineAngle.html
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