Answer:
x = 140
Step-by-step explanation:
The figure is a quadrilateral. That means it has 4 sides and more importantly for this question 4 angles. All quadrilaterals have 4 angles that add up to 360o.
You know 3 of the angles. The fourth one is x.
90 + 90 + 40 + x = 360 Combine like terms on the left
220 + x = 360 Subtract 220 from both sides.
220 - 220 + x = 360 - 220 Combine all like terms
x = 140
