The Velocity of a Plane is 625km/h Northwest

[Umbra]

Here's my work on the question which I can't help but think is incorrect, especially for c. Any tips?

 

[Ishuda]

Here's my work on the question which I can't help but think is incorrect, especially for c. Any tips?

I certainly don't see anything wrong with the answers.

 

[Umbra]

I certainly don't see anything wrong with the answers.

Oh, I guess it's good then, haha. Thank you!