Question

For circle O, mCD=125° and m

Answer 1

In the figure, ∠ ABO and ∠ BCO have measures equal to 35°.

Explanation:

Correct for plato

Answer 2

CA is a diameter of the circle, so
`m\widehat{AC}=180^\circ`, which means
`m\angle AOB=m\angle AOD=m\widehat{AD}=180^\circ-m\widehat{CD}=55^\circ`. Then
`m\boxed{\angle ABO}=90^\circ-55^\circ=35^\circ`.

This means
`m\angle CBO=55^\circ-35^\circ=20^\circ`. Also, if
`m\angle AOB=55^\circ`, then
`m\angle BOC=180^\circ-55^\circ=125^\circ`, which in turns tells us that
`m\boxed{\angle BCO}=180^\circ-20^\circ-125^\circ=35^\circ`.