Answer:
2406 miles
Explanation:
Let A be the starting position, B the junction position and C the final position after flying the 3.5 hrs. Also, let b be the distance from the starting point:
[tex]\angle ABC =(180-10) \textdegree=170\textdegree[/tex]
#Distance traveled in 1.5hrs is;
[tex]c=690x1.5\\=1035mi[/tex]
#Distance traveled in next two hrs:
[tex]a=690\times 2\\=1380mi[/tex]
#Now using the Cosine Rule:
[tex]b^2=a^2+c^2-2ab\cos B\\\\=1380^2+1035^2-2(1380)(1035)cos170\textdegree\\\\b^2=5788.83\\\\b\approx 2406.00 \ mi[/tex]
Hence, the pilot is 2406 miles from her starting position.