College Algebra & Trigonometry, 2018a

498 CHAPTER 11. THE LAW OF SINES THE LAW OF COSINES
Example 2
A pilot flies an airplane in a straight path for 2.5 hours and then makes a course
correction, heading 10 ◦ to the left of the original course. The pilot then flies in this
direction for 1 hour. If the speed of the plane is a constant 350 mph, how far is
the plane from its starting position?
Again, we’ll start by making a diagram:
C
10
◦
170 ◦
B
A
In this problem, we’ll be working with triangle ABC, shown below. We can calculate
the lengths of AB and BC from the information given in the problem and
use this to calculate the length of AC:
C
a = 350
b
∠B = 170 ◦
c = 875
A