Answer:
C
Step-by-step explanation:
The total of the arc measures is 360
DE is the only one that hasn't got a marking. Add up all the rest
80 + 20 + 30 + 50 +DE + 100 = 360 Add the left side
280 + DE = 360 Subtract 280 from both sides
280 - 280 + DE = 360 - 280
DE = 80
The answer is C
