What is this symbol? and can someone solve this algebra equation for me ?

What is the image of c for a 90° counterclockwise rotation about a? (3, 7) (-1, 3) (7, 3)

Over the course of a month, a person's weight decreases. what type of relationship is this? a. positive relationship

There are 18 female students and 16 male students in a class. which of the following expresses the ratio of female students to male students in simplest form? а) 10 b) 9 to 8 c) 8: 9 d)18/16