Answer
The birds should go 42.8 degrees West of South.
Work Step by Step
We first find the value of the angle using trigonometry:
$sin\theta = \frac{5.1}{7.5} \\ \theta = sin^{-1}(\frac{5.1}{7.5})\\ \theta = 42.84^{\circ}$
The birds should go 42.8 degrees West of South.
