Every point on a flat map can be described two ways: how far right and how far up it sits (rectangular, or Cartesian), or how far away and in which direction it lies (polar). Engineers, surveyors, and game developers hop between the two constantly — a robot arm thinks in angles and reach, while its control software thinks in x and y. The translation is the Pythagorean theorem plus a dash of trigonometry: the radius r is the square root of x² + y², and the angle θ is the arctangent of y over x. Take the textbook 3-4-5 triangle: enter 3 as Variable A (the x, horizontal distance) and 4 as Variable B (the y, vertical distance), and the Result gives a radius of 5, with the angle at about 53.13°. AC circuit analysis is the classic working use — impedance has a magnitude and a phase angle, which is polar form wearing an engineer's hat. Navigation does the same: a ship 3 miles east and 4 miles north of port is 5 miles away on a bearing you compute the same way.

With the pre-filled defaults — Variable A 10, Variable B 5 — the Rectangular To Polar Calculator returns Result 50.0000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.