Question

Write the equation in standard form for the circle with center (9, - 4) and radius 9.

Answer 1

Answer:

$(x-9)^{2}+(y+4)^{2}=81$

Step-by-step explanation:

we know that

The equation of a circle in standard form is equal to

$(x-h)^{2}+(y-k)^{2}=r^{2}$

where

(h,k) is the center

r is the radius

In this problem we have

$(h,k)=(9,-4)$

$r=9\ units$

substitute

$(x-9)^{2}+(y+4)^{2}=9^{2}$

$(x-9)^{2}+(y+4)^{2}=81$ ----> equation of the circle in standard form