Answer:
5.543 miles
Explanation:
The law of cosines can help with this. It relates side "c" of a triangle to the other two sides (a, b) and the angle between them (C).
c² = a² +b² -2ab·cos(C)
c² = 3² + 3² -2·3·3·cos(135°) = 18(1 -cos(135°)) ≈ 30.7279
c ≈ √30.7279 ≈ 5.543 . . . . miles