Answer:
c. 47.7 m
Step-by-step explanation:
If you draw a right triangle to represent the problem, the catheti are the vertical distance from the bird's eyes to the field mouse and the separation from the field mouse to the base of the tree. The 50° of depression is measured from the horizontal in clockwise, the angle that summed with the 50° of the depression can be called α. Then:
α+50=90
α=90-50=40°
The trigonometric function than relates te two catheti with the angle α is:
tan(α)=opposite/adjacent
tan40=40/x
x=40/tan40=40/0.8390=47.7m
