Assuming two non-null vectors A and B, if the component of vector A along the direction of vector B is zero, then it can be concluded thatthe vectors are perpendicular.
For instance, let vector A be (x, 0). Any vector B of the form (0, y) is perpendicular to vector A. It is easy to note how the vectors are perpendicular in this example since their directions are along the x and y axis, but the property holds for any given pair of vectors.
