Answer:
72 degrees
Step-by-step explanation:
A straight line has a measure of 180 degrees. If you subtract 144 degrees from the 180 degrees, you're left with 36 degrees as one of your inside angle measures. Like a straight line, the angles inside any triangle add up to 180 degrees. So subtract 36 degrees from 180 degrees and you're left with 144 degrees. Since the remaining 2 angles inside the triangle are congruent, they have the same measurement. So all you have to do is divide 144 by 2 and you're left with 72 degrees as your x value.
