[NEED HELP], Menu UI following mouse via rotation

I need help for a script which describes the image below.
What I’m trying to accomplish is where the mouse gets moved and the triangle moves with it via ui rotation, but it stays on a diameter/position. I’m not really good at this type of stuff so I decided to take it to dev forum after trying to look for a tutorial on doing so, but failed ultimately.
If anybody can help, it would mean a lot, Thank you!
[If not clear, the arrow UPWARDS, is the mouse.]

If you know trigonometry, you can use the rules of a unit circle for this; where the origin is the center of the image, and the normalized vector from the origin to the cursor describes the position on the unit circle. And then from there use those arc functions to derive the angle


Basically, the unit circle is what you should be looking for. If you need help, there’s plenty on online resources and tutorials on using them


Thank you! ill look for more tutorials online, if you have any to link that would be a great help