## haleym96 Find the center and radius of a circle that has a diameter with endpoints (-9, -6) and (-1,0). Show work. a) center (4,3); radius 5 b) center (8,6); radius 10 c) center (-5,-3); radius 5 d) center (-10,-6); radius 10 one year ago one year ago

1. CalebBeavers

Center would be the midpoint between those two points, and the radius would be the distance between them divided by 2

2. haleym96

So I do the midpoint formula using the two points to find the center?

3. Hero

Graph paper would work great for this problem

4. CalebBeavers

Yep, use the midpoint formula

5. CalebBeavers

What do you get?

6. haleym96

(-5,-3)

7. CalebBeavers

8. haleym96

I know its suppose to be 5, but I didn't get it.

9. CalebBeavers

Do you know the distance formula?

10. haleym96

Wait, I think I know why..

11. haleym96

I still didn't get it. Isn't it d=$\sqrt{(x2-x1)^{2}+(y2-y1)^{2}}$

12. CalebBeavers

Yeah thats it. Plug in your coordinates $D=\sqrt{(-1+9)^2+(0+6)^2}$

13. CalebBeavers

youll get d=sqrt{100} d=10 but remember thats the diameter, radius is diameter divided by 2. 10/2=5

14. haleym96

Oh, I got it now. I just added wrong. Thanks!

15. CalebBeavers

You're welcome