Help!! This is my last question on my test.

Which equation represents the partial sum of the geometric series?

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)

The center of the circumscribed circle lies on line segment and the longest side of the triangle is equal to the of the circle.