## luisz 3 years ago Farial inscribed a quadrilateral ABCD in a circle, as shown below. If the measure of arc BCD is 220°, what is the measure of angle BCD?

1. luisz

2. luisz

yeh!!!

3. luisz

any tips?

4. LoveYou*69

I don't know:( I am sorry, I will try to get someone who will know here tho!:D

5. luisz

ty

6. luisz

k

7. luisz

so did you get someone?

8. luisz

ty

9. terenzreignz

Are you sure it's the measure of angle BCD you want? you just gave its measure...

10. luisz

yes, we need the measure of angle BCD...

11. luisz

I mean arc!!!!!!!!!!!!!!!!

12. luisz

sorry

13. luisz

no

14. luisz

I mean angle

15. luisz

sorry

16. legoauto220

|dw:1340465784240:dw| Like this? IS the image correct? And we have to get the angle now, the angle C

17. luisz

Yes, angle BCD

18. THE_PROPHET

70

19. luisz

can you tell me how?

20. luisz

why is at 70?

21. luisz

its correct but why?

22. legoauto220

Because 360-220=140, and the central angle is double the angle in the circumfrence, so its 70

23. luisz

ty

24. luisz

I thought the same exact thing

25. legoauto220

|dw:1340466383693:dw|

26. luisz

I wasn't sure if it was correct, though.

27. luisz

ty

28. legoauto220

np

29. THE_PROPHET

angle BOD =140 centre is O angle subtended by chord on cente is twice the angle subtended on the circle .....so 2x = 140 x = 70

30. luisz

let me post another problem...