If two vectors A and B are such that a + b is equal to a minus b then the angle between a and b is

If two vectors A and B are such that a + b is equal to a minus b then

1.	If two vectors A and B are such that a + b is equal to a minus b then the angle between a and b is
Answer» The angel is of 90 degree bcoz insuch type of cases a parrallelogram is formed