BRAINLY IF CORRECT!!!
Does anyone know what the s inside the angle mean. The symbol?

Answer: I'm 90% sure that the S inside the angle is spatial points
The full Definition of the symbol combination is approximately equal to Spatial points?
Step-by-step explanation:
I searched s inside angle symbol and these are my results. "The angle symbol is a mathematical symbol that is placed ahead of character s, usually uppercase italic letters representing spatial points, to describe a geometric angle formed by the intersection of two lines, line segments, or rays." I'm sorry if I'm wrong.