Consider the attached picture. It represents a vector, centered in the origin with angle 41.7 degrees, and a circumference with radius 25, centered in the origin.
As you can see, the horizontal and vertical components of the vector correspond to the lengths of segments OD and OC, respectively.
You might recognize this scenario from you trigonometry class: if the circle had radius 1, we would have

Since the circle has radius 25, we have to scale those coordinates:

Answer:
correct option is C. 3.7 km
Step-by-step explanation:
given data
A to Port B = 4.7 km
lighthouse = N73°E
lighthouse = N31°E
solution
we get here first
B and
here
A = 90 - 73 = 17°
B = 73 - 31 = 42°
and
sum of all angle 180° so
A +
17° + 42° +
C = 180°
solve it we get
C = 121°
Now we use here sin law that is
........................2
put here value and we get
solve it we get
b = 3,7 km
so correct option is C. 3.7 km
Possible values = 3.0 and 6.0
6 - 3 = 3
The difference is 3
You gotta move that b to the side ya digg