## anonymous one year ago C is the center of the circle. Find the length of arc QPR http://media.education2020.com/evresources/2092515_f52585a6-6270-4c6d-939b-0093b7f0cc71.png

1. anonymous

2. anonymous

i think th formula for this is A= theta/360 *pi*r^2 but im not sure.

3. anonymous

@dan815 ?

4. anonymous

WILL GIVE MEDAL!!

5. anonymous

@Luigi0210

6. DanJS

hi

7. anonymous

hi. Can you help with this question please?

8. DanJS

sure. The Radius is 15, so the total circumference of that circle is $C = 2*\pi*r = 30\pi$

9. anonymous

ohh

10. anonymous

wait so.. what was the formula for this?

11. DanJS

Circumference of a circle is 2 times pi times the radius

12. DanJS

They want the length of arc QPR which is some fraction of that total circumference

13. anonymous

A. S=23.55 B. S=47.10 C. S=70.65 D. S=141.30

14. anonymous

Would it be D?

15. jim_thompson5910

@huaman you said that i think th formula for this is A= theta/360 *pi*r^2 but im not sure that formula is for figuring out the AREA of a pie slice like you see below |dw:1441588452712:dw|

16. DanJS

Angle QCR = 90, so the rest of that is 360 - 90 =270 Arc QPR goes around 270 of the 360 total circumference, or 3/4

17. anonymous

so C?

18. DanJS

$QPR = 2*\pi*15 *(\frac{ 270 }{ 360 })$

19. anonymous

ohh taht makes so much more sense. Thank you very much. I got C.

20. DanJS

a fraction (270/360), of the total distance around the circle 2*pi*15

21. DanJS

yep yep