Question

A circle is centered at (−4, −6) and has a radius of 3. Which of the following is the equation for this circle?

(x + 4)^2 + (y + 6)^2 = 3
(x − 4)^2 + (y − 6)^2 = 9
(x − 4)^2 + (y − 6)^2 = 3
(x + 4)^2 + (y + 6)^2 = 9

Answer 1

any help? stuck on this

Answer 2

A?

Answer 3

Clarification: are those expression being squared?

Answer 4

yes

Answer 5

It would be D. (x-h)^2 + (y-k)^2 = r^2 is the equation of a circle.

Answer 6

Assuming (h,k) is the center.

Answer 7

Thank you

Answer 8

Of course.

Answer 9

(h,k) is the center. r is the radius. So in your first example,
(x+2)2+(y−3)2=10

We would rewrite that like this so that it fits the form I posted:
(x−−2)2+(y−3)2=(10−−√)2


So now we see that h is -2, k is 3 and r is sqrt(10)
That means that the center of the circle is (-2,3) and the radius is sqrt(10)