<h2>
Answer:</h2>
This is easy. All you need to do is set up a <u><em>proportional relationship</em></u>.
A proportional relationship uses variables to show similarities, in this case, in triangles.

<u><em>x</em></u> represents the missing side.
Answer:
x = (6 - y)÷ 3
Step-by-step explanation:
3x + y = 6
3x = 6 - y
x = 6 - y ÷ 3
Answer:
1) 5/6
2) 18/10 (mixed fraction is 8)
3) 13/6 (mixed fraction is 6⅙)