How many triangles?

pudley4 · #1 08-27-2006, 01:22 AM

I'm putting together an Amazing Race for some friends and family. One of the tasks is to identify how many triangles are in the following picture:

I just want someone to double-check my work [img]/images/graemlins/smile.gif[/img]

LondonBroil · #2 08-27-2006, 01:38 AM

At first glance, I see 9, but I'm sure there's more . [img]/images/graemlins/wink.gif[/img]

soah · #3 08-27-2006, 01:58 AM

I'm reasonably sure that there are no less than 18. I counted 21 at one point but I think I counted a few of them twice.

durron597 · #4 08-27-2006, 02:24 AM

I count 25.

Labeling the regions helped me stay organized:

My answer in white below:

<font color="white">
1 piece triangles
8
A,B,C,E,F,G,H,I

2 piece triangles
8
AB,AC,CD,CE,DF,EF,FH,GH

3 piece triangles
5
ACE, BDF, BDG, CDG, EFH

4 piece triangles
2
CDEF, EFHI

5 piece triangles
2
ABCDG, BDFGH
</font>

pudley4 · #5 08-27-2006, 08:30 AM

Yeah Durron, that's exactly what I did and exactly what I came up with.