Answer:
x = 20
Step-by-step explanation:
4x and 5x are same- side interior angles and sum to 180° , then
4x + 5x = 180
9x = 180 ( divide both sides by 9 )
the two angles are same-side interior angles, thus, the two angles add up to 180°
=> 4x + 5x = 180
=> 9x = 180
=> x = 20
