To find the measure of \(\angle COA\), we can use the fact that the angles around point \(O\) add up to \(360^\circ\).
Given:
- \(m\angle BOA = 180^\circ\)
- \(m\angle BOC = 110^\circ\)
Since \(m\angle BOA\) and \(m\angle BOC\) share point \(O\) and there are two angles around it, we can define the angles involved:
\[ m\angle AOB + m\angle BOC + m\angle COA = 360^\circ \]
We know:
- \(m\angle BOA = 180^\circ\)
- \(m\angle BOC = 110^\circ\)
Now, since \(\angle AOB\) and \(\angle BOC\) are not directly adjacent, we can rewrite:
\[ m\angle COA + 110^\circ = 180^\circ \]
This is because \(m\angle BOA\) (which is \(180^\circ\)) is formed by the sum of \(m\angle BOC\) and \(m\angle COA\):
\[ m\angle COA = 180^\circ - m\angle BOC \]
Substituting \(m\angle BOC\):
\[ m\angle COA = 180^\circ - 110^\circ = 70^\circ \]
So, the measure of \(\angle COA\) is \(70^\circ\).
Thus, the answer is: \[ \boxed{70^\circ} \]