The equation $(x - 7)^2 + (y + 13)^2 = 12$ represents a circle. What is its radius?
Standard formula for a circle
(x-h)2 + (y-k)2 = r2
SO for this equation r2 =12 so r = sqrt(12) = 2 sqrt 3
The radius of the circle is 2.
+73 
