How do I find degrees in transversal lines?

The circumference of a circle is 60 pi cm3what is the radius of the circle

The transitive property of equality states that: o if a = b, then bra o if a = b, then ac = bc o if a = b and b= c, then a = if a = b and c= c, then a + b = b + c

The center of a circle represent by the equation (x+9)^2+(y-6)^2=10^2 (-9,6), (-6,9), (6,-9) ,(9,-6)