如何用整数值（不是向量）计算两行之间的度数

I'm working on small effect animation where it creates 5 distinctive objects expanding in 5 different directions from the center. The objects should not stack on each other so i'm thinking about distributing them in separated angles of circle but i don't know how to calculate the angle between two randomly created lengths of lines in px (for example: 100px line and 50px line)I'm working on small effect animation where it