Question

Find the equation of a circle with a center at (–7, –1) where a point on the circle is (–4, 3).


(x + 7)2 + (y + 1)2 = 25
(x - 7)2 + (y - 1)2 = 25
(x - 7)2 + (y - 1)2 = 5

Answer 1

i think that would be the first one

Answer 2

The equation of a circle with center (h,k) and radius r is: (x-h)^2 + (y-k)^2 = r^2

Here (h,k) is (-7,-1) and you can find the radius by finding the distance between (-7,-1) and (-4,3).

Answer 3

@ranga the radius is 5. so what do you do next?

Answer 4

Put h = -7, k = -1, r = 5 in (x-h)^2 + (y-k)^2 = r^2

Answer 5

oh. nevermind you just plug them in. So would it be the last one?

Answer 6

Try again.

Answer 7

the middle one?

Answer 8

(x - h) = (x - (-7)) = (x + 7)
(y - k) = (y - (-1)) = (y + 1)

Answer 9

im confused.

Answer 10

Put h = -7, k = -1, r = 5 in
(x-h)^2 + (y-k)^2 = r^2
(x-(-7))^2 + (y-(-1))^2 = 5^2
(x+7)^2 + (y+1)^2 = 25

Answer 11

okay.