Unity 2d C# - Orbit object around another objects center using mouse position

Hello everyone, I am working on my first 2d game. I have a ball I can pull back and release, the ball then shoots around the stage. When I pull back, I would like to show an arrow that shows what direction the ball will go. The arrow will rotate around the ball, opposite side of the ball than the mouse is on. The further I pull back, the more the arrow image will grow in length. I have my image on the screen, and I have it so when I MouseDown and dragging the arrow is shown, once I release the mouse I hide the arrow. I am not sure how to position the base of the arrow on a circular path around the ball and coordinate it with the mouse position.