## anonymous one year ago A circle is centered at (7, 8) and has a radius of 11. Which of the following is the equation for this circle? (x − 7)^2 + (y − 8)^2 = 121 (x − 7)^2 + (y − 8)^2 = 11 (x + 7)^2 + (y + 8)^2 = 121 (x + 7)^2 + (y + 8)^2 = 11

1. anonymous

will donate medal to best answer

2. misty1212

HI!!

3. anonymous

@jim_thompson5910 @mathstudent55 @ganeshie8 @misty1212

4. anonymous

hi :)

5. misty1212

make a guess, i bet you are right general form is $(x-h)^2+(y-k)^2=r^2$ put $$h=7,k=8,r=11$$

6. anonymous

so (x-7)^2+(y-8)^2=11^2 ?

7. misty1212

yeah although they need you to square 11

8. anonymous

ok

9. anonymous

so (x^2+49)+(y+64)=121 ?

10. anonymous

@misty1212 ?

11. anonymous

@jim_thompson5910

12. anonymous

D:

13. anonymous

oh no!!

14. anonymous

can you help me ?

15. anonymous

just take what you wrote above

16. anonymous

$(x-7)^2+(y-8)^2=11^2$

17. anonymous

(x^2+49)+(y+64)=121 ?

18. anonymous

all @misty1212 was saying is that in your answer choices the 11 is squared

19. anonymous

so does that matter or not ?

20. freckles

are you trying to expand the square parts?

21. anonymous

22. anonymous

i dont know im bad at geometry

23. freckles

$(x-7)^2=(x-7)(x-7)=x(x-7)-7(x-7)=x^2-7x-7x+49 \\ =x^2-14x+49$ no your choices do not have this form

24. anonymous

im confused

25. anonymous

D: D: D:

26. freckles

$(x-h)^2+(y-k)^2=r^2 \\ \text{ you are give} (h,k)=(7,8) \text{ and } r=11 \\ \text{ just plug into this form }$ I think @satellite73 already walked you though this

27. freckles

replace h with 7 replace k with 8 replace r with 11

28. anonymous

yes

29. anonymous

(x-7)^2+(y-8)^2=121 ?

30. freckles

that is right

31. anonymous

tnx u deserve the medal