g is the vector (6, 3), since it starts at the origin and terminates at the point (6, 3).
We can write this as a sum of the scaled unit vectors (1, 0) and (0, 1),
(6, 3) = (6, 0) + (0, 3)
where (6, 0) is the x-component of g and (0, 3) is the y-component. The lengths of these component vectors are clearly 6 and 3, respectively.