Answer:
x = 20°
Step-by-step explanation:
Consecutive interior angles theorem
The pairs of consecutive interior angles formed when two parallel lines are cut by a transversal are supplementary (sum to 180°).
⇒ 4x + 5x = 180°
⇒ 9x = 180°
⇒ x = 20°
4x+5x=180
9x/9=180/9
x=20
