Question

The equation of the circle whose center is (0, 0) and radius is length 9 is

x² + y² = 3
x² + y² = 9
x² + y² = 81

Answer 1

The formula for a circle is:
(x-h)^2 + (y - k)^2 = r^2
(h,k) = center coordinates
What do you think it is then?

Answer 2

and r = radius

Answer 3

i mean lol I think it should be number 1

Answer 4

No.
Your radius is 9
if the equation is equal r^2
9^2 is?

Answer 5

I dont know why but im doing a lesson online and it says 9 is wrong ?

Answer 6

It's not 9 -.-

Answer 7

(x-0)^2 + (y-0)^2 = 9^2
x^2 + y^2 = 81

Answer 8

??? I guess not i alredy tried it 2 and it was wrong ?

Answer 9

\[\large (x-h)^2 + (y-k)^2 = r^2\]
\[\large h = 0 , k = 0 , r= 9\]
\[\large x^2 + y^2 = 81\]

Answer 10

I think it could be right thanks.