Question

Write the equation of a circle with center P(0, -3) and radius 8.

a.) x2 + (y + 3)2 = 64
b.) x2 + (y - 3)2 = 64
c.) (x - 3)2 + (y + 3)2 = 64
d.) (x - 3)2 + y2 = 64

Answer 1

Hint:

\[\Large (x-h)^2 + (y-k)^2 = r^2\]

is the general equation of a circle. The center is (h,k) and the radius is r.

Answer 2

thank you

i got b

Answer 3

you are close

Answer 4

but b is incorrect

Answer 5

ohh um ill try again hang on

Answer 6

notice in choice b how there is a "y-3"

compare y-3 with y-k

this tells us that k = 3 and the y coordinate of the center is 3

Answer 7

is it a?

Answer 8

but we want the y coordinate of the center to be -3

Answer 9

it is because y+3 is the same as y - (-3)

Answer 10

i just realised that its two negatives that make a posotive

Answer 11

that's one way you can think of it

Answer 12

thank you

Answer 13

you're welcome