### Instruction: A circle is centered at $O$, $\overline{AB}$ is a diameter and $C$ is a point on the circle with $\angle COB = 50^\circ$.  What is the degree measure of $\angle CAB$?### Response: I know that the measure of an angle inscribed in a circle is half the measure of the central angle subtended by the same arc.
So, if $\angle COB = 50^\circ$, then $\angle CAB$ must be half of that, or $25^\circ$.