11. i got it by realizing that if we are looking at only upward pointing triangles i would take out the ones facing down. then i would have a pyramyd with only upward tryangles. then i would count. 1+2+3+4= 10 plus the one that all of them form altogether. so my final answer would be 11.
I agree with ben because i did exactly as told by his instrucytions but it is very tricky because i almost missed one so you have to be aware and check
I got 19. Remember you have to count all of the small ones. Then the whole thing is one then three up-right and one down-right make one. There are a couple of those. At the end I got 19.
the first thing i did was count all the triangles that were facing upward then i counted the triangle that holds all of the triangles.then i got the answer
I agree that there are 19, first I counted all the small ones and got 10 then I counted the next size and got 6 then the next size after that I got 2 and then the whole triangle counts as 1 and then I added them up all together and got 19.
label each triangle a-z. then list all of the possible combinations for instance: 4 small triangles that make up a big triangle would be marked as triangle abcd. then you add up all the possible triangles
How many upward-pointing triangles (of any size) are in the diagram at the right?
19 comments:
The first step that i would take is that i would count all of the triangles that i can see are facing upward.
11. i got it by realizing that if we are looking at only upward pointing triangles i would take out the ones facing down. then i would have a pyramyd with only upward tryangles. then i would count. 1+2+3+4= 10 plus the one that all of them form altogether. so my final answer would be 11.
I agree with ben because i did exactly as told by his instrucytions but it is very tricky because i almost missed one so you have to be aware and check
hint...
try counting the number of "upward facing" triangles from each point.
(there are more than 11)
I got 19. Remember you have to count all of the small ones. Then the whole thing is one then three up-right and one down-right make one. There are a couple of those. At the end I got 19.
I got 20 you have to look closely at the big triangle and try to see them!
Can you suggest any organized way of counting?
this is really hard but i got 19
I got 15. It is prob. wrong but, i cant find any more.
I got 19 also My suggestion to figuring out the problem is that at first you should count all of the smaller triangles and then the bigger one.
for every big triangle there is as many little ones... if you count them all up i got 20 triangles pointing up including the whole thing its self
the first thing i did was count all the triangles that were facing upward then i counted the triangle that holds all of the triangles.then i got the answer
I agree that there are 19, first I counted all the small ones and got 10 then I counted the next size and got 6 then the next size after that I got 2 and then the whole triangle counts as 1 and then I added them up all together and got 19.
i agree that there are 19 but if there is a much bigger triangle is there a more mathematical way of counting them?
The way icounted them was if you start with the biggest ones than you move towards the middle with the smaller ones
I think it is 19 b/c I first counted the smaller triangle and then the larger ones and then the whole one.
I would first count all the small triangles. then i see bigger ones that are made up of the smaller ones. i would do that till i can't find any more.
label each triangle a-z. then list all of the possible combinations for instance: 4 small triangles that make up a big triangle would be marked as triangle abcd. then you add up all the possible triangles
So, if you made a chart that had "one unit" triangles that are pointing up - how many are there? 10
Then you can look for "2-unit" but those aren't triangles! What about "3-unit" triangles? - none of those either.
So, 4-units are next. I count 6.
So, my final chart would look like this:
UNITS # of triangles
1 10
4 6
9 3
16 1
TOTAL 20
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