Answer
$19^{\circ} 59^{'} 24^{"}$
Work Step by Step
RECALL:
$1^{\circ} = 60^{'} \text{ and } 1^{'} = 60^{"}$
\begin{equation}
\begin{split}
19.99^{\circ} &= 19^{\circ}+0.99^{\circ} \\ & = 19^{\circ} + 0.99 \times (1)^{\circ} \\ & = 19^{\circ}+0.99 \times (60)^{'} \\ & = 19^{\circ}+59.4^{'} \\ & = 19^{\circ}+59^{'}+0.4^{'} \\ & = 19^{\circ}+59^{'}+0.4 \times (1)^{'} \\ & = 19^{\circ}+59^{'}+0.4 \times (60)^{"} \\ & = 19^{\circ}+59^{'}+24^{"}
\end{split}
\end{equation}
Thus, $19.99^{\circ} = 19^{\circ} 59^{'} 24^{"}$