Question

What is the equation of a circle with center of (4,6) and radius of 5?
a.xx+yy=25
b.(x+4)^2+(y-6)^2=5
c.(x-4)^2+(y+6)^2=5
d.(x-4)^2+(y+6)^2=25

Answer 1

none of them is right....
the last one should be y-6

Answer 2

equation of circle:
\[(x-h)^{2} + (y-k)^{2} = r^{2}\]
where center is (h,k)

Answer 3

I agree with lalay.

Answer 4

its d

Answer 5

you might have a typo somewhere
if its d, then center is (4,-6)

Answer 6

ya...but how do u get the answer?

Answer 7

from the standard equation of a circle i posted above

Answer 8

I hv the key, but I dont know how to solve

Answer 9

the right side is always the radius squared
the left side has (x-h)^2 and (y-k)^2 where (h,k) is center of circle

Answer 10

so given the center and radius, you can write the equation of the circle

Answer 11

example: center is (1,3) and radius is 2
2^2 = 4 --> right side is 4
plug in 1 for h and 3 for k
left side is (x-1)^2 + (y-3)^2
put it together
--> (x-1)^2 + (y-3)^2 = 4

make sense

Answer 12

wat would be x and y, then???
how could u solve for that???

Answer 13

its not asking you to solve for x and y
it just wants the equation of the circle

Answer 14

o.o THANK YOU!!!

Answer 15

no problem

Answer 16

and wen lalaly was saying that the last one should be y-6, wat does that mean???

Answer 17

well you said the center was (4,6)
(y-k)^2 --> (y-6)^2

Answer 18

(y+6)^2 means that k = -6
y-(-6) = y+6

Answer 19

OHHHH, that's why. dumbcow, you are a lifesaver. Thank you

Answer 20

glad to help

Answer 21

Im putting up another question

Answer 22

come see it

Answer 23

wats the name for the standard equation that u used?