m < EJB = half of m < OBE.
m < BDE = 180 minus m < BOE.
m < OED = m<OBD.
Step-by-step explanation:
First part : Because angled subtended by an arc at the circumference = half of angle at the center.
Second: Because The 2 angles OBD and OED = 90 degrees.
Third: DB and DE are both tangents to the circle, and OE and OB are both radii. So m < OED = m<OBD = 90 degrees.