Notes

The coordinate plane was developed centuries ago and refined by the French mathematician René Descartes.

The decision that a circle should be labelled counterclockwise was made by the ancient Babylonians long before any surviving mathematical works, so nobody really knows why it was made. There are only guesses. My guess: when the earth is taken to be fixed, the sun revolves about the earth approximately one degree per day in the positive (= counterclockwise) direction. (Not quite one degree since it takes the sun approximately 365 days to "revolve about the earth".)

Because angles, which start at 0 degrees, travel in that direction. When an angle is at 0 degrees, it is located to the right of the y-axis, and on the x-axis. As the degrees grow larger, the angle unfolds to the left, or counter-clockwise.

The idea of this system was developed in 1637 in writings by Descartes and independently by Pierre de Fermat, although Fermat also worked in three dimensions and did not publish the discovery.

The development of the Cartesian coordinate system would play a fundamental role in the development of the calculus by Isaac Newton and Gottfried Wilhelm Leibniz.[3]

The three dimensional Cartesian coordinate system provides the three physical dimensions of space—length, width, and height