Simon built a Polar to Cartesian converter (Simon’s own code). You can enter the radius in pixels and the angle in degrees, click “convert” and you get the coordinates in x and y and a circle appears n that spot.
You are welcome to play with Simon’s converter online in CodePen at: https://codepen.io/simontiger/pen/MmdodP
Simon is also planning to make a similar converter for Spherical to Cartesian (where you would enter radius, latitude and longitude and convert those into x,y,z).
Here Simon explains the formulas to convert between Polar and Cartesian coordinates: