Answer:
The answer is D), 80.
Step-by-step explanation:
All sides of a triangle must add up to 180°. So, if x = 100, angle BCA must equal 60° because 180 - 120 = 60. Since angles BCA and DCE are vertical angles, they are equal, making angles DCE 60°. All you need to do now is add up 60 + 40; that should give you 100. You also need to subtract that from 180 to get your final answer of y = 80°.
