Plz asap features of a circle from its expanded equation last one

We have the following equation:
 x2 + y2 + 6y - 72 = 0
 Rewriting we have:
 x2 + y2 + 6y = 72
 Complete squares we have:
 x2 + y2 + 6y + (6/2) ^ 2 = 72 + (6/2) ^ 2
 x2 + y2 + 6y + (3) ^ 2 = 72 + (3) ^ 2
 x2 + y2 + 6y + 9 = 72 + 9
 x2 + (y + 3) 2 = 81
 So, the center is:
 (0, -3)
 The radio is:
 r = 9
 
 (0, -3)
 r = 9