$\begin{align}   & \widehat{A}=28{}^\circ \Rightarrow \overset\frown{DC}=2\widehat{A}=2\left( 28 \right)=56{}^\circ  \\  & \overset\frown{AC}=180-56=124\Rightarrow \widehat{B}=\frac{\overset\frown{AC}}{2}=\frac{124}{2}=62{}^\circ  \\ \end{align}$