Question 188054
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The Standard Form of an Equation of a Circle is given by:
<font color=blue>(x-h)^2 + (y-k)^2 = r^2</font>
Where: <font color=blue>r</font>=radius; <font color=blue>h,k</font>=center; <font color=blue>x,y</font>=point on the circle


Given:  center (4,-3)= (h,k); radius= r = 9 
It follows---> {{{(x-4)^2+(y-(-3))^2=9^2}}} ---> {{{highlight((x-4)^2+(y+3)^2=81)}}} ---> Standard form with center (4,-3);
and radius = 9.
See below,
{{{drawing(400,400,-15,15,-15,15,graph(400,400,-15,15,-15,15),blue(circle(4,-3,9)),red(circle(4,-3,.12)),green(locate(3.2,-3,center)),green(arrow(4,-3,13,-3)),red(locate(7,-2,r=9)))}}}
Thank you,
Jojo</font>