The given vector is
[tex]m=\langle16,-21\rangle[/tex]
The formula to find the direction angle is
[tex]\theta=\tan ^{-1}|\frac{y}{x}|[/tex]
Replacing each coordinate, we have
[tex]\theta=\tan ^{-1}|\frac{-21}{16}|=52.7[/tex]
Therefore, the direction angle is 52.7°, approximately.
