Answer:
20.1°
Step-by-step explanation:
Put the given numbers into the given formula and do the arithmetic.
∆L = 1050/(60·cos(29.5°)) ≈ 20.1°
The change in longitude is about 20.1 degrees.
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Additional comments
A degree is 60 minutes: 1° = 60', so 30' = 0.5°.
This formula is accurate when the distance units are nautical miles.
