Question

Can anyone help me with Circle in the Coordinate Plane?......i cant wrap my head around this stuff to save my life ive been going over the book and quiz i need for days but nothing tells me how to solve the questions.

Answer 1

Sure... can you be more specific? :)

Answer 2

If you could post a specific question, for an example, I'll see what I can do~

Answer 3

The center of a circle is (h,7) and the radius is 10. the circle passes through(3,-1). Find all possible values of h.

Answer 4

Okay... you know how to get the equation of a circle, when you're given its center (h,k) and its radius r?

Answer 5

ummmmm.....i may but i wanna be sure....this is important

Answer 6

Okay :)
If you're given the center \(\large (\color{red}h \ , \ \color{green}k)\) of a circle as well as its radius \(\large \color{blue}r\)

then the equation of the circle is
\[\Large (x-\color{red}h)^2 + (y-\color{green}k)^2=\color{blue}r^2\]

Answer 7

ok......so how should the plug ins be placed?

Answer 8

Well, what are your values for h, k, and r?

Answer 9

h is what you need. k is 7 and r is 10?

Answer 10

That's correct :D
\[\Large (x-\color{red}h)^2 + (y-\color{green}7)^2=\color{blue}{10}^2\]
\[\Large (x-h)^2 + (y-7)^2 = 100\]

Catching me so far?

Answer 11

ok.....now how does the (3,-1) fit in? im guessing thats the x,y?

Answer 12

YES Exactly :D
\[\Large (\color{red}3-h)^2+(\color{blue}{-1}-7)^2=100\]
Are you sure you needed help with this? :3

Answer 13

well ive been having problems with geo all year and this counts for alot since i got my final dropped so need to be absolutly sure i know what im doing

Answer 14

Okay, so can you solve that ^ equation now?
It's just a quadratic equation in one variable... use whatever method suits you... but if you get stuck, call me ;)

Answer 15

i certainly will thank you so very much

Answer 16

No problem :)

Answer 17

terenzreignz .....what determins the symbol inside the perenthesis?

Answer 18

what?

Answer 19

the symbol inside ( )....like - or +

Answer 20

I'm not getting, need to be more specific...

Answer 21

the standerd equation is (x-h)^2+(y-k)=r^2....what would make be (x+h)^2+(y-k=r^2 or the other way around?

Answer 22

not x+h but x-h

Answer 23

yeah what would determine the difference

Answer 24

what do you mean by "the other way around" ?

Answer 25

either (x-h)+(y-k)....(x+h)+(y-k)....or (x-h)+(y+k)

Answer 26

Oh... if the center has positive coordinates, then
(x-h) and (y-k)
if the center has negative coordinates, then you'd have pluses...
for instance, if the center was (-4 , 2)
then it'd be
(x+4) and (y-2)

Answer 27

ohhhhhhhhhhhhhhhhhhhhh....ok thank you much.....makes sense now

Answer 28

sorry i confused you

Answer 29

:)