Question

Which is an equation of the circle with a radius of 9 units and center at
(–4, 2)?
(x − 9)2 + (y + 4)2 = 4
(x − 4)2 + (y + 2)2 = 81
(x + 4)2 + (y − 2)2 = 81
(x − 2)2 + (y + 4)2 = 81

Answer 1

@Teddyiswatshecallsme do you know this?

Answer 2

Equation of a circle:
\[(x - h)^2 + (y - k)^2 = r^2\]

Answer 3

h and k represent the x and y coordinates of the center of the circle

Answer 4

r represents the radius

Answer 5

The center is (–4, 2) and h represents -4 and k represents 2. 9 is the radius of the circle and we have to square that = 81.

Answer 6

okay that makes sense. i just googled it after awhile

Answer 7

Okay so now plug those values into the original formula of the circle

Answer 8

(x+4)^2 +(y-2)^2 = 81

Answer 9

Correct :)

Answer 10

So what answer should that be?

Answer 11

c

Answer 12

Yup

Answer 13

could you help me with another one?

Answer 14

Sure. Just post it separately

Answer 15

okay