Hello,

the sum of two vectors can be described as the diagonal in a parallelogram with the vectors as its sides. The difference of two vectors gives the second diagonal in this parallelogram.

If then you are dealing with a rhombusandthe diagonals are perpendicular that means you are dealing with a right triangle. (See attachment)

The angle between the vectors is . the ratio of the length of the diaogonals is 1 : 100. Thus

. That means:

Now you can calculate the angle between the vectors. I've got:

EB