The measure of minor arc is 84 degree
The expression for the an angle inscribed in a circle, then the measurement of the angle is equal to the half of the measure of its intercepted arc.
[tex]\text{Angle}=\frac{1}{2}m(arc)[/tex]here we have, arc length = 84 degree
[tex]\begin{gathered} m\angle ADC=\frac{1}{2}(mAC) \\ m\angle ADC=\frac{1}{2}\times84 \\ m\angle ADC=42^o \end{gathered}[/tex]Angle = 42 degree