## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$1.73 \ square \ units$
We apply the area formula: $k=\dfrac{1}{2} b \ c \sin A$ Plug in the given data. Therefore, $k=\dfrac{1}{2} (4)(1) \sin (120^{\circ}) \approx 1.73 \ square \ units$