+0  
 
0
145
4
avatar

How many distinct triangles can be drawn using three of the dots below as vertices?

 

 Jul 13, 2020
 #1
avatar+28021 
+1

I count 14 ....  anyone else?   (edited)

 Jul 13, 2020
edited by ElectricPavlov  Jul 13, 2020
 #3
avatar+732 
0

i got 18... i'm  not sure if im right though

lokiisnotdead  Jul 13, 2020
 #2
avatar+732 
+2

hmm I think a better approach to this problem is to use complementary counting.

 

There are \(\dbinom{6}{3}=20\) ways to choose 3 points to make a triangle. However  of these ways are just straight lines, so \(20-12=\boxed{18} \text{ triangles. }\)

 

I'm not sure if this is right, so please let me know if it's correct or not! 

:)

 Jul 13, 2020
 #4
avatar+111626 
+1

Hi Loki,

Your logic sounds good to me.   cool

 

 

you have a typo though  wink

Melody  Jul 13, 2020

24 Online Users

avatar
avatar