Answer:
58.0 units
Step-by-step explanation:
In order to use the law of sines, we need to know angle C. It will be the angle that brings the total of all angles to 180°.
C = 180° -A -B = 180° -72° -16°
C = 92°
The law of sines tells us ...
a/sin(A) = c/sin(C)
a = c·sin(A)/sin(C) = 61·sin(72°)/sin(92°)
a ≈ 58.0 . . . . units
