Answer
The distance between points A and B is approximately 3.7 miles
Work Step by Step
Here one can directly use the law of cosine:
$AB^2=4.2^2+5.6^2-2(4.2)(5.6)\cdot cos(42º)$
$AB^2=17.64+31.36-47.04\cdot 0.74$
$AB^2=49-34.96$
$AB=\sqrt{14.04}\approx 3.7$ mi
