Question

Graph the circle with center at (-4, 2) and radius 5. Label the center and at least four points on the circle. Write the equation of the circle.

Answer 1

What equation do you think you can write about this?

Answer 2

drawing's a bit off.... there's just one detail I can't shake off haha

Answer 3

Im gonna add the points in, just wait

Answer 4

Don't you think that circle's too small? :)

Answer 5

well I cant make it exact with drawing

Answer 6

Granted, but the origin should be inside the circle.
And it should cross the y-axis, the radius is 5, after all, longer than the distance of the centre from the y axis :D

Answer 7

Not at all haha

Answer 8

whats the equation

Answer 9

tell us what you've come up with so far @wyattp17

Answer 10

im lost bc u guys both are confusing me

Answer 11

We can't just give you an equation, we need to know that you understand

Answer 12

Here's how to do it... if you know the centre of the circle, as well as its radius, then the equation will be easy to dish out...

say, the center is \(\large (\color{red}h,\color{green}k)\) and the radius is \(\large \color{blue}r\)

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

Answer 13

then explain

Answer 14

^

Answer 15

ok so its (-4- H)^2 + ( 2-k) 2 = 5

Answer 16

What? No, lol, don't touch the x's and y's.

Your centre should replace (h,k) and not (x,y)

And note the square on the r.

Answer 17

wait so the -4 and 2 go in the H and K spot ?

Answer 18

Yup. ^^

Answer 19

-4 for H?

Answer 20

Yes...

Answer 21

ok

Answer 22

(x--4)^2 + ( y-2)^ 2 = 5 ^2

Answer 23

--4?
What happens when you have two -'s? haha

Answer 24

oops typo

Answer 25

Fix it.

Answer 26

(x+4)^2 + ( y-2)^ 2 = 5 ^2

Answer 27

That's right :)

And there's your equation ^^

And there's no way you'd be able to get that into y = _______ form. haha

Answer 28

ok is that it ?

Answer 29

whats the center

Answer 30

Well, you could change 5^2 into 25...

Answer 31

What do you mean what's the centre, it's given in your bloody question haha

Answer 32

thx

Answer 33

Anytime :)
Well, not really
haha

@drumminboy918 wrap it maybe? :)

Answer 34

@PeterPan how do i get the points