## anonymous 4 years ago if arc AB measures 155 degrees (14 cm), what is the length of the radius of the circle, to the nearest hundredth? drawing.........

1. anonymous

|dw:1342158548525:dw|

2. anonymous

3. anonymous

...i just dont know how to solve it

4. anonymous

http://en.wikipedia.org/wiki/Arc_(geometry) $\frac{arc degree}{360}=\frac{arclength}{circumference}$ http://en.wikipedia.org/wiki/Arc_(geometry) $\frac{arc degree}{360}=\frac{arclength}{circumference}$ $\frac{155}{360}=\frac{14}{2\pi*r}$ Using cross multiplication: $155*2\pi*r=14*360$ Solve for r. Note: I got 5.17, so someone wrote it down wrong (either you or the teacher!)

5. anonymous

lol i was just going to ask if i could cross multiply

6. anonymous

omg thanks.

7. anonymous

8. anonymous

lol

9. anonymous

and teachers says to NOT use wikipedia.

10. anonymous

Probably because it's not a truly vetted source. It is better to use your book to find the equation. If you google something (e.g. arc length) and find multiple pages on the net have the same equation, then you're probably good. Having said that your book is always your best source!

11. anonymous

i dont have a book, i have online schooling and its a test so i cant go back to look at how to solve it.

12. anonymous

Why'd the teacher tell you the answer to a test question?

13. anonymous

so i could learn how to solve it.