Hello,

Question

What are the different formulas for circles (radius, circumfrence, diameter, area)?

Thank you

Answer 1

LOL, you have to be more explicit about what you want. For example:
x^2 + y^2 = r^2
is a formula for a circle of radius r and center at the origin in x,y plane

Answer 2

google is your friend. Try searching for

circle area circumference

and so on, and you will get many explanations and examples.