How do you write an equation for a circle with center (2,-1) and radius 3?

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Answer 1 · 2016-02-20T19:18:52

The required equation is
#(x-2)^2 + (y+1))^2=9#

The distance formula is

#sqrt((x-h)^2+(y-k)^2) =r#

Now,equation of a circle is

#((x-h)^2+(y-k)^2) =r^2#

Thus,an equation for a circle with center (2,-1) and radius 3 is

#(x-2)^2 + (y-(-1))^2=3^2#

#(x-2)^2 + (y+1))^2=9#