First, you have to define your x and y axes, what is 0º and what direction do you turn to face 90º.... In algebra, the 0º is the angle from the x-axis, and you turn counter clockwise to get to 90º (the y-axis)
but if you use the compass directions, 0º (north) is the y axis, and you turn CLOCKWISE 90º to get to the x-axis (east)
