Now, I'm not really sure what angleConverted is. I'm assuming it's some type of radians to degrees formula
It is the other way around, angleConverted is in radians, the formula for conversian between degrees/radians is:
degrees / 360 = radians / 2pi
or equivalently:
radians = 2pi * degrees / 360

All points on a circle have the same distance, r to the center. You can form a triangle between the center, a point on the circumference of the circle and the x axis. Using the rules that:
1) The sine of an angle is the ratio of the length of the opposite side to the length of the hypotenuse.
2) The cosine of an angle is the ratio of the length of the adjacent side to the length of the hypotenuse.
We get that the x coordinate is cos(angle)*r, and the y coordinate is sin(angle) * r.
In your code these are reversed, the effect is that angle 0 is to the bottom, instead of to the right.
If you use different radii in the x and y direction you will get a point on some kind of ellipse.