<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:
a
Step-by-step explanation:
X/15=4/16 def of similar triangle by AAA
x = 60/16=5/2