Questions   
Sort: 
Mar 29, 2015
 #1
avatar+130518 
+5

 

 

I'll give this one a shot......but....I'm not overly confident.....!!!

Notice the follwing patterns......

For a 1 x 1 square, we have two possible values fo x and y, 0 and 1. And we have two ways to pick an apex point  and a base of 1. But, we can orient these two triangles in 4 ways......apex points at the "top," apex points to the "right," apeax points to the "left" and apex points on the "bottom"....and each will have a base of 1...so that's eight possible triangles

1x 1 =   (2 apex points)*(1 base) * [4 orientations]  = 8 possible triangles 

 

For a 2 x 2   square, we have three possible values for x and y  .... 0, 1, 2.  And we have three possible apex points,  three possible bases -  two of one unit and one of two units, and three possible heights - two of one unit and one of two units. And these can be oriented in 4 different ways, as before.

So the possible triangles in a 2 x 2 configuration are....

2 x 2  = [3 apex points]*[3 possible bases]* [3 possible heights]* [4 possible orientations]  = 108 possible triangles

 

And for our situation, we have a 3 x 3 square.

We have four possible values for x and y - 0,1,2,3. And we have four possible apex points, 6 possible bases and heights- three of one unit, two of two units and three of one unit.... and four possible orientations, as before.

So....the possible triangles are

3 x 3 =  [4 apex points]* [6  bases] *[6 heights]*[4 possible orientations ] =  576 possible triangles

 

It appears that the pattern for an n x n arrangement is [n + 1]*[C(n+1, 2)]^2 * 4  

-------------------------------------------------------------------------------------------------------------------------

I hope this is correct........can somebody else check my reasoning ????

 

 

    

Mar 29, 2015
 #1
avatar+4711 
0
Mar 29, 2015

0 Online Users