The boat in discuss is 9.03 miles from lighthouse B.
The distance of the boat from lighthouse B as required can be determined by means of the cosine law in which case we have;
c² = 10² + 6² - (2×6×10Cos 63)
c = 81.52
c = 9.03miles.
Read more on cosine rule;
https://brainly.com/question/2491835
#SPJ1