In an inscribed quadrilateral, opposite angles are supplementary. This means that the measures of the angles must add up to \(180^\circ\).
Given that \(m \angle M = 54^\circ\), we can find \(m \angle A\) as follows:
Since the arcs in the circle correspond to the angles opposite to them, we have:
-
The arc from \(A\) to \(T\) measures \(50^\circ\): This means the inscribed angle \(\angle M\) subtended by arc \(AT\) would measure half of the arc: \[ m \angle M = \frac{1}{2} \times 50^\circ = 25^\circ \]
-
The arc from \(T\) to \(H\) measures \(170^\circ\): Thus, the inscribed angle \(\angle A\) subtended by arc \(TH\) would measure: \[ m \angle A = \frac{1}{2} \times 170^\circ = 85^\circ \]
Now, recall that \(m \angle A + m \angle M = 180^\circ\). Since \(m \angle M\) was found through arc \(AT\), we actually want to consider the relationship correctly:
Using \(m \angle A + m \angle M = 180^\circ\), where \(m \angle M = 54^\circ\): \[ m \angle A = 180^\circ - 54^\circ = 126^\circ \]
Thus: \[ m \angle A = 126^\circ \]
So, the final answer is: \[ \boxed{126} \] degrees.