Question

The center of a circle is at (−3, 1) and its radius is 9.

What is the equation of the circle?


(x+3)2+(y−1)2=18

(x−3)2+(y+1)2=18

(x−3)2+(y+1)2=81

(x+3)2+(y−1)2=81

Answer 1

Your answer is (x+3)²+(y−1)²=81

Answer 2

The standard form of the circle equation is in the form
`(x-h)^(2)+(y-k)^(2)=r^(2)` with the center being at the point
`(h,k)` and the radius being "r".

We have to find the equation of circle with center (-3,1) and radius as 9.

So, h= -3, k=1 and r=9

Equation of circle is:

`(x-(-3))^(2)+(y-1)^(2)=(9)^(2)`

`(x+3)^(2)+(y-1)^(2)=81` is the required equation of the circle.

Therefore, Option 4 is the correct answer.