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How many different sized triangles can be formed using 2 cm,3cm,4cm,5cm and 6cm rods?

 Apr 30, 2020
 #1
avatar+924 
+2

A triangle has to have the sum of the two smaller legs to be greater than the largest leg.

 

2x3x4

3x4x5

3x4x6

4x5x6

 

There are 4 triangles.

 

EDIT: Wrong Answer...CPhill has the right answer.

 Apr 30, 2020
edited by HELPMEEEEEEEEEEEEE  May 1, 2020
 #2
avatar+528 
+2

It could simply be C(5, 3) as we are choosing 3 rods from the 5 total, therefore resulting in 10.

But, 6 of these will be degenerates (i.e. the sum of the 2 smaller legs is less than the bigger leg).

 

So, there are 4. Can someone verify this? :D

 

EDIT: Wrong Answer

 Apr 30, 2020
edited by CentsLord  Apr 30, 2020
 #3
avatar+111456 
+2

2, 3, 4 , 5 , 6

 

I get these   ???

 

2 , 3 , 4

2,  4,  5

2,  5,  6

3,  4,  5

3,  4,  6

3,  5,  6

4,  5,  6

 

 

cool cool cool

 Apr 30, 2020
 #4
avatar+924 
+1

Yeah.. I just realized I was missing some triangles!

 Apr 30, 2020

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