Click and drag on the sprites to move the arc! Press space to change how the arc's segment length is determined. You drag the sliders to set the variables. Segment length is the distance of each line of the arc. Angle length is the portion of the circle that each line of the arc covers.
I decided to share this because it took me a LOT of work. I was inspired to make this in order to draw a stage for @GUIDED_BY_A_MAP'S Oh No! MAP. Since I didn't get the part, I'll be making my own AMV, and this arc will be part of my artwork. Credit to all of my math teachers, past and present, for their dedication and diligent tutelage. Particularly seventh and eighth grade, for algebra and geometry. Credit to AutoCAD for the name and idea of making an arc based off three points. Finally, credit to the Scratch Team, for making a work environment where such things as this are possible. Thank you! Feel free to use the scripts, with or without credit.