How did oxygen get into the earths atmosphere in its early days? plz explain

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west