Question

Circle S has an equation of (x + 16)^2 + (y – 9)^2 = 4. What is the center and radius of circle S?
Answer
Center: (16, -9); Radius: 4
Center: (-16, 9); Radius: 4
Center: (16, -9); Radius: 2
Center: (-16, 9); Radius: 2

Answer 1

do you know the formula of the circle ?

Answer 2

\[(x-h)^2+(y-k)^2=r^2\]
where (h,k) is the center and r is the radius

Answer 3

want to take a stab at the answer, tahtah?

Answer 4

thats why i just call h Cx and k Cy

Answer 5

uhhhhhhmmmmmmmm one sec

Answer 6

you have it in just the form you want
\[(x + 16)^2 + (y – 9)^2 = 4\]
\[(x-h)^2+(y-k)^2=r^2\]

Answer 7

identify h, k and r

Answer 8

would it be A?

Answer 9

definitely not a, because
r^2=4
r=2

Answer 10

Oh im slow. So is it C then?

Answer 11

@Dockworker \[\Large if \quad r^2=4 \longrightarrow r=\pm\sqrt{4} \quad ??\]

Answer 12

not c either, its d
you can rewrite the equation to better help you see
\[(x-(-16))^2+(y-9)^2=2^2\]

Answer 13

@Kreshnik, we're dealing with a radius here. you can discard the negative value.

Answer 14

:P

Answer 15

oh darn i was not close at all. Thank you <3

Answer 16

\[r^2=4\implies r=2\]
\[16=-h\implies h=-16\]
\[-9=-k\implies k=9\]
center is \((-16,9)\) radius is 2