Using the cosine theorem we have the following equation:
d ^ 2 = (800) ^ 2 + (840) ^ 2 - 2 * (800) * (840) * (cos (150-45))
We cleared d:
d = root ((800) ^ 2 + (840) ^ 2 - 2 * (800) * (840) * (cos (150-45)))
d = 1301.327321
Nearest whole number:
d = 1301 miles
Answer:
The airplanes are far about:
d = 1301 miles