for the math majors, fun with triangles

lotus776 · #1 10-25-2005, 07:44 PM

Given fourteen points draw equidistant to each other in the shape of a pyramid missing the top piece (5 bottom row, 4 the row above, 3 the row above that and finally two on the row above that which is the top), determine the number of triangles that can be drawn formed with the vertices at these points.
the picture should look like Pascals Triangle without the top point . I don't know how to draw the image of the dots properly on this website. Imagine 14 dots arranged in a pyramid without a top piece. Please give a brief explanation. good luck, have fun!

-Brent

hint: the answer is a prime number and is not 329, this is a statistics problem, the triangles do not have to be equilateral

JoshuaD · #2 10-25-2005, 08:14 PM

lotus776 · #3 10-25-2005, 09:48 PM

yes, that picture is correct

#4 10-25-2005, 10:36 PM

ugh, was doing this and realized you said the triangles didn't need to be equilateral...back to step 1.

EDIT:
Does this have to do with the Euler thingy?

#5 10-27-2005, 06:16 PM

Did you forget about us? more hints please I can't solve it...am I right with saying it has to do with Eulers thingy?

Siegmund · #6 10-27-2005, 07:45 PM

When you posted this problem last week, two different methods of arriving at 329 were posted.

Could you kindly tell us what the flaw was with those? I'm sure I am not the only one who has independently reproduced 329 as an answer.