What is the equation of a circle with center (-3, -5) and radius 4?

2 Answers
Mar 7, 2016

(x+3)2+(y+5)2=16

Explanation:

A general circle with centre (a,b) and radius r has equation (xa)2+(yb)2=r2.

So in this particular case the equation is

(x+3)2+(y+5)2=16

Mar 7, 2016

x2+y2+6x+10y+9=0

Explanation:

(xa)2+(yb)2=r2
a=3 b=5 r=4
(x+3)2+(y+5)2=42
(x+3)2+(y+5)2=16
x2+6x+9+y2+10y+25=16
x2+y2+6x+10y+9=0