Question

In the figure O is the center of the circle. If AB=BC and angleAOB=70 then angleOBC is

Answer 1

Consider triangle AOB and triangle OCD

OA=OB=OC=OD=radius

∠AOB=∠DOC=70

In △OCD

OD=OC

∠ODC=∠OCD

∠OCD+∠ODC+∠DOC=180

2∠OCD=180

o

−70

o

∠OCD=55

o

=∠ODC

See the photo if it doesn't make sense