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experimentX
 2 years ago
how many triangles do you see in figure.
experimentX
 2 years ago
how many triangles do you see in figure.

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experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5let's see, we have 1 huge triangle

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5the no of smallest triangle is 9+7+5+3+1 = 26

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5a little bigger triangle .. we have 13, so total is 40 until now

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5no .. but quite close

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5Oo... sorry @King 's right i made mistake in above summation

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5can you explain your approach?

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.59+7+5+3+1 = 26 .. from this i was able to deduce 46

King
 2 years ago
Best ResponseYou've already chosen the best response.2nos.of small triangles=25 not 26!!@experimentX

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5still i cannot come up with general formula ...!

King
 2 years ago
Best ResponseYou've already chosen the best response.2no.of triangles=level of @experimentX

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.0Wait letme count again

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5lol ... quite a matching no.

King
 2 years ago
Best ResponseYou've already chosen the best response.2no.of small triangles=25 no.of triangles with 2 rows of small triangles=10 no.of triangles with 3 rows of small triangles=6 no.of triangles with 4 rows of small triangles=3 1 big full triangle so, 25+10+6+3+1 =45!!

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5no.of triangles with 2 rows of small triangles=10 ...it think this should be 13, aren't we missing inverted triangles?

.Sam.
 2 years ago
Best ResponseYou've already chosen the best response.0If overlapping I found 45

Callisto
 2 years ago
Best ResponseYou've already chosen the best response.0not include the inverted ones :(

King
 2 years ago
Best ResponseYou've already chosen the best response.2there are no inverted ones wid 3 or 4 rows so it has to be 48...i think

King
 2 years ago
Best ResponseYou've already chosen the best response.2@experimentX u der?if u are happy and satisfied wid answer close the question....

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5i guess 48 is the right answer ...

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5still i was looking some sorts of permutations and combinations to this get this answer ... anyway thanks to all who tried.

philips13
 2 years ago
Best ResponseYou've already chosen the best response.0floor(n(n+2)(2n+1)/8) where n is the number of triangles on a side in your specific case, n=5

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0if this problem is only about the dark triangles it is kind of boring... isn't it about using the inverted ones as well as callisto suggested?

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0actually, I'm seeing more problems with the solution here isn't there much more going on that we are ignoring?

FoolForMath
 2 years ago
Best ResponseYou've already chosen the best response.1@philips13 Gave the right answer. \[\huge \lfloor \normalsize \frac{ (n(n+2)(2n+1)}8 \huge \rfloor \]

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0Oh yeah? Ok thanks, but now I wanna decipher it you seem to be familiar with this theorem FFM :P

FoolForMath
 2 years ago
Best ResponseYou've already chosen the best response.1I am familiar with almost everything labelled interesting :P http://www.mathematik.unibielefeld.de/~sillke/SEQUENCES/gridtriangles

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0You think we haven't noticed? Where do you get this encyclopedic knowledge?!

FoolForMath
 2 years ago
Best ResponseYou've already chosen the best response.1Lol, I was kidding. I am just an ordinary guy with some practice :)

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0yeah, whatever... :P I'm not sure I understand some of the notation on the link you gave me, but I'm sure I'll get it after hacking away at it for a while. Thanks :D

Callisto
 2 years ago
Best ResponseYou've already chosen the best response.0I was thinking why i couldn't get the answer 48 when i did the calculation. But then from the website, it says that number of triangle = n*(n+2)*(2n+1)/8 for n even = (n*(n+2)*(2n+1)  1)/8 for n odd So, I got 48 finally... BTW, it's experimentX who first suggested that we were missing the inverted triangles

experimentX
 2 years ago
Best ResponseYou've already chosen the best response.5thanks to all for reply!! and finally it's complete!
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