
Answer:
Perpendicular to the x-axis:  at an angle of 90° to the x-axis
Therefore, 4 units perpendicular to the x-axis is:  y = ±4
Perpendicular to the y-axis:  at an angle of 90° to the y-axis
Therefore, 5 units perpendicular to the y-axis is:  x = ±5
Quadrant I:  (x, y)  →  (5, 4)
Quadrant II:  (-x, y)  →  (-5, 4)
Quadrant III:  (-x, -y)  →  (-5, -4)
Quadrant IV:  (x, -y)  →  (5, -4)