A full circle is 360 degrees.
Each segment in the picture is given a degree except for DE,
To find DE subtract all the given degrees from 360:
DE = 360 - 40 - 30 - 20 - 90 - 110 = 70 degrees.
Now to get BE add: BC + CD + DE
BE = 30 + 40 + 70 = 140 degrees.