Triangle offspring

Four equilateral triangles. Prove that the three black line segments are concurrent.

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Solution by Stéphane Bernard.

You just need the intercept theorem. // segments in green and yellow fig. have the same ratio which is equal to the ratio, on their common side, of the segments created by the intersection of the sides so the intersecting sides must concur in the same point.


Please find here the video solution: Video: Triangle offspring.

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