Drag the target anywhere — try all four quadrants, and the vertical axis
θ from atan(y / x) — one argument
+53.13°
Correct here: quadrant I is inside atan's range.
θ from atan2(y, x) — two arguments
+53.13°
Signs kept: x > 0, y > 0 → quadrant I.
x (down-field)
+3.00
y (left)
+4.00
range √(x²+y²)
5.00 m
ratio y / x
+1.3333
reference angle a
53.13°
sign pair → quadrant
(+, +) → I
atan2 − atan
0.00°