<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:
9 sides
Step-by-step explanation:
Given the sum of the interior angles = 1260°, then
180° (n - 2) = 1260 ( divide both sides by 180 )
n - 2 = 7 ( add 2 to both sides ), hence
n = 9
Answer:
h= -28
Step-by-step explanation:
h+14=-14 isolate h by subtracting 14 on both sides
h= -28