## anonymous one year ago Radius OA of circle O has a slope of 2.5. What is the slope of the line tangent to circle O at point A? 0.8 2.5 -0.4 -5

1. amoodarya

|dw:14351729953:dw

2. amoodarya

|dw:1435173081679:dw| $\frac{HA}{oH}=2.5$ is this ? what you mean ?

3. anonymous

um i guess...it's cause the problem doesn't include a picture

4. amoodarya

|dw:1435173229389:dw|

5. amoodarya

you can draw an image (it help you to better understanding) slope (oA) , slope(tangent line) =-1 because they are perpendicular

6. amoodarya

now you must guess the answer ! can't you ?

7. anonymous

i dont know! i honestly dont know /:

8. amoodarya

if two line are perpendicular ...with slope $m_1 ,m_2$ so relation between them is : $m_1.m_2=-1\\m_1=2.5\\so\\m_2=?$

9. amoodarya

m2 =?

10. anonymous

-3.5? idk!

11. amoodarya

$2.5 *m_2=-1\\m_2=\frac{-1}{2.5}=\frac{-1}{\frac{5}{2}}\\=\frac{-2}{5}$

12. anonymous

-0.4

13. amoodarya

bravo

14. anonymous

yaaay! thank you!

15. amoodarya

understand ?

16. anonymous

yes (:

17. amoodarya

it is not better to change your Id to igetmath ?

18. anonymous

you dont like my id name? lol

19. amoodarya

i live mathematics