+0  
 
0
206
5
avatar

How many Isosceles triangle can you make from the dots like below ?

 

 Oct 28, 2019
 #1
avatar+397 
-1

Assume the base of the triangle is on the bottom four points because a congruent triangle can be made by reflecting the base on the top four points. For a triangle with a base of length 1, there are 3 triangles. For a triangle with a base of length 2, there are 3 triangles. For length 3, there are 2. In total, the number of non-congruent triangles is 3+3+2=8.

 Oct 29, 2019
 #2
avatar+23562 
0

Isosceles triangles?    I can find 12

ElectricPavlov  Oct 29, 2019
edited by Guest  Oct 29, 2019
 #3
avatar+397 
0

but if you can rotate it of reflect it to be the same, it is counted twice.

sinclairdragon428  Oct 29, 2019
 #4
avatar
0

Can you show me an isosceles triangle in the diagram with base lenght two?  ...or three?   Remember....two sides need to be of the sam length....

Guest Oct 29, 2019
 #5
avatar+23562 
0

Hmmmm....  ALL 12 of my triangles have the equal side lengths of 1.....and 4 have bases 0f 3    I guess there is only two that can be found?

  The question says nothing about rotating/flipping being the same triangle.....   I still think there is 16.....reflected / rotated / flipped makes it another triangle in the diagram  .....   IMO  cheeky

 Oct 29, 2019
edited by ElectricPavlov  Nov 1, 2019

16 Online Users

avatar
avatar
avatar
avatar