Re: Complete the equation?

Quote:

Originally Posted by

**M670**

YES and

You should know the basic algebra: .

Re: Complete the equation?

Hello, M670!

You're making hard work out of it . . .

The equation of a circle with center and radius is: .

You already know the center: .

You need only the radius . . .

. . Use the Distance Formula.

Re: Complete the equation?

Quote:

Originally Posted by

**Plato** YES and

You should know the basic algebra:

.

So I came up with but that still isn't right and I dont know why? I need to write formula =0

Re: Complete the equation?

Quote:

Originally Posted by

**M670** So I came up with

but that still isn't right and I dont know why? I need to write formula =0

You did not use the fact , did you?

Re: Complete the equation?

Quote:

Originally Posted by

**Plato** You did not use the fact

, did you?

No I did not use the as I know the circle formula to be [tex](x-h)^2+(y-K)^2=r^2[/tex} since it's asking me for the equation equal to zero I am not sure where I would put radius?

Re: Complete the equation?

Quote:

Originally Posted by

**M670** No I did not use the

as I know the circle formula to be [tex](x-h)^2+(y-K)^2=r^2[/tex} since it's asking me for the equation equal to zero I am not sure where I would put radius?

I don't think any of us can help you understand this question.

Your misunderstanding is very profound.

Please sit down with a live tutor. Go over what this question means.

Re: Complete the equation?

Quote:

Originally Posted by

**Plato** I don't think any of us can help you understand this question.

Your misunderstanding is very profound.

Please sit down with a live tutor. Go over what this question means.

Thanks for trying, Its this web program called webworks, It really sucks as you have to answer it a specific way or esle it wont except it.

Re: Complete the equation?

You know that the centre is and one point on your circle is . The radius is the distance between the centre to any point on the circle, so how can you work out the distance between these two points?

Re: Complete the equation?

Quote:

Originally Posted by

**Prove It** You know that the centre is

and one point on your circle is

. The radius is the distance between the centre to any point on the circle, so how can you work out the distance between these two points?

Yes I know I can use the standard distance formula which will give my radius of the circle but the question was asking me the equation of a circle with its center at (-7,9) and passes throught points (4,1)

Re: Complete the equation?

Quote:

Originally Posted by

**M670** Yes I know I can use the standard distance formula which will give my radius of the circle but the question was asking me the equation of a circle with its center at (-7,9) and passes throught points (4,1)

Well damn it, use it!

Re: Complete the equation?

I don't think you've bothered reading the posts above you. If you have the centre and radius of your circle, substitute them into this:

where is the centre of your circle and is the radius.

This is the general form of the equation of a circle. But since you are asked to set the equation equal to 0, you expand everything and move everything to one side.

Re: Complete the equation?

Ok So which is then

HOLY SH** it just dawned on me is the correct answer....

Let's hope it doesn't take me this long on my final...

Many thanks Prove it and Plato...

Re: Complete the equation?

Actually so which means .