Ok, I''m a doofus, I''m drawing a complete blank and whats worse is that my reference books may as well be on Mars (away from home right now), not to mention that the search for the forums is not functioning right now. From the top of my head given a triangle with points ABC, 1. D = midpoint of AB 2. E = midpoint of BC 3. midpoint X = the intersection of AE and CD. Drawing it on paper looks as if it is correct, but without my references I can''t be sure. Yes I googled. Am I close? Did I win a cigar? Thanks in advance. D.V. Carpe Diem

Hi!

To calculate the mid point of a triangle whit points A, B, C just do it like this:

Mid = (A + B + C) / 3

There is not such thing as the mid point of a triangle. Or there are several mid points, depending on how you look at it. What you described will give you the barycenter, which is one reasonable "mid point". (A+B+C)/3 will also give you the barycenter.

What do you need the "mid point" for?

Thanks, nothing like a Monday morning brain fart

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Original post by alvaro
What do you need the "mid point" for?

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I want to tessalate a three sided based pyramid (4 faces) (I know a pyramid has a four sided base, can''t remember its name though, yet another brain fart), so that it has 12 faces and then again 36 faces etc....

just something I''m knocking around right now.


D.V.

Carpe Diem

Hmm im no expert but you didnt say ANYTHING about a pyramid. What you need to do is to read at the article "How to ask questions the smart way".

As a side note,
(A + B + C) / 3 is the orthocenter.
Where the three medians (perpendicular lines through the midpoint of each side) intercept is the barycenter, and does not necessarily lie within the circle. The orthocenter and incenter will do.

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Original post by AxoDosS
Hmm im no expert but you didnt say ANYTHING about a pyramid. What you need to do is to read at the article "How to ask questions the smart way".

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I am going to assume he said this to get you to go here:
http://www.tuxedo.org/~esr/faqs/smart-questions.html

Have you seen the movie Memento? We should take a picture of MrWugga and write a sentence below it: "Don''t believe his lies"

Let''s clarify some things:

Medians: lines that join vertices to middle points of the opposite side.
"Mediatrices" (Spanish name for them, not sure about a translation): perpendicular lines through the midpoint of each side.
Heights (not sure; it''s "alturas" in Spanish): perpendicular lines from a vertex to the opposite side.
Bisectrices (Spanish again): Lines that pass through a vertex, dividing the corresponding angle in half.

Medians cross in the barycenter (guaranteed to be inside the triangle).
Mediatrices cross in the circumcenter (?), which is the center of the circle passing through all the vertices (could be outside the triangle).
Heights cross in the orthocenter (could be outside the triangle).
Bisectrices cross in the incenter, which is the center of the circle tangent to all three sides (guaranteed to be inside the triangle).

(A+B+C)/3 is the baricenter (not the orthocenter).

You can find a big bunch of "mid points" of a triangle here:
http://mathworld.wolfram.com/topics/TriangleCenters.html

I learned:

draw a line cetner of AB to C
draw a line cetner of BC to A
draw a line cetner of AC to B

then where the lines meet, thats the center!