Answer:
<DOC = <AOB =50* as opposite angles.
<DOE + <DOC + <EOA = 180*, thus <EOA = 180-50-60 =70*.
<COB + <AOB = 180*, thus <COB = 130*.
// Central angles equal the arcs they rely on.
Arc AE = <EOA = 70*.
Arc AB = <AOB = 50*.
Arc ECB = <EOD + <DOC + <COB = 60+50+130 = 240*.
Arc BOC = <COB = 130*.
