Vertical angles are equal in measure. Therefore, we can set the measures of the two angles equal to each other:
\[ m∠4 = m∠2 \]
Given:
\[ m∠2 = 135° \]
and
\[ m∠4 = (4x + 15)° \]
Setting them equal:
\[ 135 = 4x + 15 \]
Now, we will solve for \( x \):
- Subtract 15 from both sides:
\[ 135 - 15 = 4x \]
\[ 120 = 4x \]
- Divide both sides by 4:
\[ x = \frac{120}{4} \]
\[ x = 30 \]
Thus, the value of \( x \) is \( 30 \).
Answer: 30