Tag Archives: parallel

Interesting geometry result, again

To show that the angle bisector of an angle in a triangle splits the opposite side in the ratio of the two adjacent sides.

My first proof used angles in the same segment. See

https://howardat58.wordpress.com/2014/05/14/interesting-geometry-result/

Several tries later (today) and i came up with this annoyingly simple proof:Bisector of angle in a triangle splits

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Filed under geometry, math, teaching

Geometry test. Maybe simple ! Try it.

Three maybe parallel lines, AD BE CF
Two transversals, AC DF
question how many parallel
Given that AB is equal to BC and DE is not equal to EF
(“equal” = “congruent” if you like)
show that at most two of the maybe parallel lines can be parallel.
(proof by contradiction is a last resort)

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Filed under abstract, geometry, Uncategorized