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Third Morley Triangle


MorleysThirdTriangle

The third Morley triangle is made by rotating line BC toward vertex A about vertex B by angle (B+4pi)/3. It is an equilateral triangle.

It has trilinear vertex matrix

 [1 2cos[1/3(C-4pi)] 2cos[1/3(B-4pi)]; 2cos[1/3(C-4pi)] 1 2cos[1/3(A-4pi)]; 2cos[1/3(B-4pi)] 2cos[1/3(A-4pi)] 1]
(1)

(Kimberling 1998, p. 165).

Its signed side lengths are

 a^'=b^'=c^'=8Rsin[1/3(A-4pi)]sin[1/3(B-4pi)]sin[1/3(C-4pi)]
(2)

giving an area of

 A=16sqrt(2)R^2sin^2[1/3(A-4pi)]sin^2[1/3(B-4pi)]sin^2[1/3(C-4pi)].
(3)

The following table lists perspectors of the third Morley triangles with other named triangles that are Kimberling centers.

triangleKimberlingperspector
first Morley triangleX_(1135)4th Morley-Taylor-Marr center
reference triangleX_(1134)third Morley-Taylor-Marr center
second Morley triangleX_(1137)6th Morley-Taylor-Marr center

See also

First Morley Triangle, Second Morley Triangle

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References

Kimberling, C. "Triangle Centers and Central Triangles." Congr. Numer. 129, 1-295, 1998.

Referenced on Wolfram|Alpha

Third Morley Triangle

Cite this as:

Weisstein, Eric W. "Third Morley Triangle." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ThirdMorleyTriangle.html

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