A__ lens is sometimes called a converging lens because it

Convex;makes parallel light rays passing through it bend inward and meet (converge) at a spot just beyond the lens known as the focal point.

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