Two parallel lines are crossed by a transversal.

Alternate interior angles are congruent as per the theorem.
In order to find the value of x, set the angles equal to each other.
[tex]3x + 4 = 115\\\\ 3x = 111\\ \\ x = 37[/tex]
Hence, the value of x is 37.
Answer:
Value of x is 37.
Step-by-step explanation:
Given:
line y and line z are parallel.
line x is traversal line.
To find: value of x.
∠( 3x + 4 )° and ∠ 115° are alternate interior angle in the given figure.
We know that Alternate interior angles of parallel lines are equal.
So,
3x + 4 = 115
3x = 115 - 4
3x = 111
x = 37
Therefore, Value of x is 37.