The resultant is the vector sum of the sum of each component. The components are perpendicular, like an x-y graph. Since you only have two components altogether, your resultant is the sum of 50N along y, and 20N along x. It's given simply by

where

is the unit vector along x and

is the unit vector along y. The magnitude of

is given by the Pythagorean theorem as

Its angle above the x-axis is given by the arctangent of the y-component divided by the x-component:
