*See the figure in the attachment below
Answer:
346.4 ft
Step-by-step Explanation:
The distance between the boats, CD = BD - BC
Using trigonometric ratio formula, find the length of BD in right triangle ∆ABD, and also find the length of BC in right triangle ABC.
Length of BD in triangle ABD:
Opposite length to <30° = 300 ft
Adjacent length = BD


Divide both sides by tan(30)

(nearest tenth)
Length of BC in triangle ABC:
Opposite length to <60° = 300 ft
Adjacent length = BC


Divide both sides by tan(60)

(nearest tenth)
distance between, CD, between the boats = BD - BC
= 519.6 - 173.2 = 346.4 ft