Using proportions, the value of x that makes the triangle similar is of x = 14.
A proportion is a fraction of a total amount, and the measures are related using a rule of three.
In this problem, we want the triangles to be similar, hence the lengths of it's sides follow the proportion given next:
[tex]\frac{6}{12} = \frac{7}{x}[/tex]
Applying cross multiplication:
6x = 12 x 7
x = 2 x 7
x = 14.
The value of x that makes the triangle similar is of x = 14.
More can be learned about proportions at https://brainly.com/question/24372153
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