Answer: x = 37
Explanation: If two parallel lines are cut by a transversal,
then alternate interior angles are congruent.
So we can say that 3x + 4 = 115.
Subtracting 4 from both sides, we have 3x = 111.
Dividing both sides by 3, we find that x = 37.
So the value of x is 37.
