## K.Binks one year ago Point C is the center of the circle. Angle ACB measures 49 degrees. What is the measure of arc ADB?

1. K.Binks

2. anonymous

3. anonymous

Intuitively you would think that the degree is the same when line is drawn connecting the three points

4. anonymous

However after careful scrutiny you would notice that D is indeed not on the straight line

5. anonymous

Do you know the radius of the circle?

6. anonymous

It would be impossible to determine the length without knowing the radius unless you are talking in ratios.

7. K.Binks

I'm not really sure, I don't remember the cirlce's unit very well. Is the arc the same as the angle? or doubled? or I could be totally wrong. What I have in the question is all the information I have.

8. anonymous

9. K.Binks

How do I find that?

10. anonymous

$49 \times \frac{ \pi }{ 180 }$

11. anonymous

but it still doesnt make sense since you dont have the radius or any information of D

12. K.Binks

So then how do I answer?

13. anonymous

what options have you got?

14. K.Binks

None, this one isn't multiple choice

15. anonymous

good luck :)

16. anonymous

if the circle has a radius of 1 unit, its something close to pi*radius. thats all i can tell you, sorry

17. K.Binks

It doesn't tell me the radius or diameter at all... Thanks anyway

18. anonymous

Use the formula $l=r.\theta$ where l is arc length, r is radius and theta is the angle subtended(measured in radians) clearly r is constant for a given circle so $l_{1}=r.\theta_{1}$ and $l_{2}=r.\theta_{2}$$\frac{l_{2}}{l_{1}}=\frac{\theta_{2}}{\theta_{1}}$ Using this we can calculate for arc length $l_{2}=\frac{\theta_{2}}{\theta_{1}}.l_{1}$ Now you are neither given l1 nor theta 2, although one would think theta 2 is 180 degrees, it could be wrong, is there more information given in the question??

19. anonymous

You don't need to convert to radians here though, if u just use degrees for both angles u'll be fine as their units cancel out

20. K.Binks

No, that's it, thats all I was given

21. anonymous

Then there is definitely some information missing in the question I think, it is incomplete.

22. K.Binks

I'm just looking for the arc length, is there no way to get that from this information? I thought I just needed to find the length of AB then subtract that from 180 and the rest was ADB. But I can't solve for AB without the radius?

23. K.Binks

Or I'm completely wrong... I can just skip this one, if it cant be solved

24. K.Binks

I meant 360, not 180**

25. K.Binks

I'll just skip this one I guess, thank ya'll anyway

26. JoannaBlackwelder

If it is asking for the degree measure of the arc, it is equal to the central angle measure of the circle.

27. JoannaBlackwelder

I'm guessing that A, C, and D are supposed to be in a straight line.

28. JoannaBlackwelder

@K.Binks

29. JoannaBlackwelder

Any ideas using that info?

30. K.Binks

How do I solve for the arc measure that way? The whole circle equals 360, I'm given the arc AB, which is 49 (right?) and they're looking for arc ADB, so just 360-49= 311.. right? @JoannaBlackwelder

31. JoannaBlackwelder

Yep, perfect!