First, we identify the corresponding sides in the triangles. In the following image we can see corresponding sides in the same color:
For the triangles to be similar, there must a proportion between the corresponding sides.
A proportion is a number by which you multiply the sides of 1 triangle to get the sides of the other triangle. In this case, we can see that between the red sides there is a proportion of 2:
Also, between the blue sides there is a proportion of 2:
But, between the green sides, this proportion of 2 is not true, because 6x2 will be 12 and we have 14,
thus, the answer is:
They are not similar because corresponding sides are not proportional
