Answer:
x = 30 degrees
Explanation:
Okay so we start by noticing that the two pointed out vertices = 180 degrees. So we have the following equation.
(x + 12) + (3x + 48) = 180
If you combine them you get:
4x + 60 = 180
Subtract 60 from both sides..
4x = 120
Divide both sides by 4..
x = 30
And there's your answer!