## anonymous 4 years ago so in geometry, were going over lines that meet inside, outside, or on the circle. now i got to the point where i has the equation set up but cant figure it out. the equation is "8X+X^2=36" help?

1. anonymous

Can you please explain a bit more, did you try use the formula for solving quadratic equation?

2. anonymous

i will draw it. hold on

3. anonymous

|dw:1328752131866:dw|

4. anonymous

so line ar is 9, rb is 4 and km is 8. i need to find rk. i think i set the equation up right, but i may be wrong

5. anonymous

The length of the radius should be given

6. anonymous

its not. i gave you all the information the book gave me.

7. anonymous

I am not sure for all the information given one can set up any equation, can you please show me work

8. anonymous

Hey I am sorry, length of radius is given it is KM

9. anonymous

yeah the equation is ok. Let us see how to solve the equation $x ^{2} + 8x - 36= 0$ => $x = (-8 \pm \sqrt{8^{2} - 4*1*(-36)}) / 2 * 1$ (using quadratic equation) Since X here denote length, we will take only the positive value, hence, $x = (-8 + \sqrt{208}) * 0.5= 3.211$

10. anonymous

well i get that. but the book says its 5.3 :/

11. anonymous

i dont understand how it got 5.3 in any way shape or form