Answer
$61.71^{\circ}$
Work Step by Step
$1^{\circ} = 1 \text{ Degree} \hspace{20pt} 1^{'} = 1 \text{ Minute} \hspace{20pt} 1^{"} = 1 \text{ Second}$
$\because 1^{'} = \left(\dfrac{1}{60}\right)^{\circ} \text{ and } 1^{"} =\left(\dfrac{1}{3600}\right)^{\circ} $
Thus,
$61^{\circ} 42^{'} 21{"} = 61+\left(42 \times \dfrac{1}{60}\right) + \left(21 \times \dfrac{1}{3600}\right) \approx \boxed{61.71^{\circ}}$
