Circles: Chords, Radii, and Arcs

zee-f · 2012-11-01 10:30:57

Thank you so much for all the help and time !:)

Bob · 2012-11-01 10:44:34

That's ok.

I recommend that you get some practice by drawing a few triangles. Measure the three angles and check they add to 180.

Also try 90-45-45 for example.

Make sure you are clear about equilateral and isosceles triangles.

I've made a diagram with all the correct angles marked.

eg. BOC means the angle at O made by the lines OB and BC. You should have 120 for this.

Hint for Q16.

Split the isosceles triangle BOC in half to make two right angled triangles. Now you can calculate half of BC.

Off to bed now.

Bob

zee-f · 2012-11-01 11:10:25

16. What is the measure of chord BC? I choose
A- 6.928

thank you so much! good night

bobbym · 2012-11-01 13:11:24

Hi zee-f;

That is what I get for 16 also.

Bob · 2012-11-01 20:11:43

Me too!

Bob

zee-f · 2012-11-02 05:36:09

Ok for the question bellow I was really lazy to actually draw the circle and I said the CAB= 23 and it was incorrect then I drew a circle like the one we did yesterday and here's What I Got

AOB = 80
ABO = 50
BAO = 50

CBO = 40
BOC = 100
BCO= 40

Ok So CAB would be 50 degrees

18. If the measure of arc AB is 80 degrees, what is the measure of angle CAB?
Hint: Remember that all the angles in a triangle add up to 180 degrees.

A 13 deg
B 23 deg
C 42 deg
D 50 deg
E 37 deg
F 119 deg

bobbym · 2012-11-02 09:54:14

Hi;

It would help if you could show your drawing.

Bob · 2012-11-02 20:12:11

hi zee-f and bobbym,

If it's the same diagram as before, with new angles, then those answers all look good to me.

Bob

ps. What happened to Q17 ?

zee-f · 2012-11-03 10:09:44

Hi,

I get the same drawing the bob bundy drew but the question doesn't really say if it is the same diagram it only says:

18. If the measure of arc AB is 80 degrees, what is the measure of angle CAB?
Hint: Remember that all the angles in a triangle add up to 180 degrees.
A 13 deg
B 23 deg
C 42 deg
D 50 deg
E 37 deg
F 119 deg

I get D 50 degrees

also I got 17 correct it said 17. If the measure of arc AB is 75 degrees, what is the measure of arc BC?(I answered F)

A 27 deg
B 54 deg
C 100 deg
D 180 deg
E 160 deg
F 105 deg

Bob · 2012-11-03 10:42:00

hi zee-f

18D and 17F. Both look correct to me. Well done.

Looking back, it seems all these questions use the same diagram from post 52.

Bob

zee-f · 2012-11-03 11:46:23

Thank you guys

I am still correcting #8 and #19
I choose#8- F and it was incorrect

8. If I drew a line segment from A to C, and the radius of circle M was 1, what would line segment AC be?
A sqrt 7
Bsqrt 2
Csqrt 8
D sqrt 13
E sqrt 4
F sqrt 3

bobbym · 2012-11-03 13:19:14

Hi;

I would choose E and then shoot the questioner!

zee-f · 2012-11-03 13:21:28

LOL am confused math can get confusing sometimes

bobbym · 2012-11-03 13:22:51

Hi;

Looking at the diagram I see that line segment AC is a diameter. If the radius is 1 then the diameter is 2. Which answer equals 2?

Bob · 2012-11-03 20:23:39

hi

For question 8 don't you want the diagram below?

I thought you had this one ciorrect back at post 4.

Bob

ps. What's the question for 19 ?

zee-f · 2012-11-04 03:22:17

That's weird I think I choose 8-F by excedent because that is not what I got earlier

zee-f · 2012-11-04 04:09:47

19. If I created an imaginary point on arc AC named D, and drew line segments from points A and C to D, what would the measure of angle ADC be?

I choose F and it was incorrect.

A 60 deg
B 7.5 deg
C 30 deg
D 15 deg
E 90 deg
F 120 deg

Bob · 2012-11-04 04:31:06

hi zee-f

Look below and check that I've got the diagram right.

120 would be the arc BC.

Arc ADC is 180 because AC is a diameter; it doesn't matter where D is.

But the question asks for angle ADC.

What does that look like?

Bob

zee-f · 2012-11-04 04:59:57

So i use the same diagram from #18?

Bob · 2012-11-04 06:16:41

Well what other choice is there? The questioner seems to like using the same diagram over and over so, in the absence of any other instruction, I think you've got to. The 'right' answer is in there amongst the multi-choices.

What do you think it is?

Bob

zee-f · 2012-11-04 06:27:22

I don't get how it says that the point is on the arc so AC is the arc and I draw a point on it? confusing

zee-f · 2012-11-04 06:32:08

I think it is 30 degrees

Bob · 2012-11-04 06:40:12

It just means choose any point on the circumference between A and C

So look again at my diagram.

We want the angle ADC. It's not 30. Again my diagram is accurate. Time for that protractor again I think.

Bob

zee-f · 2012-11-04 06:40:35

but i think i should add 60 +30 which gives me 90

zee-f · 2012-11-04 06:43:31

I drew a circle and the first half is 30, 30, 120 the second is 60 60 60 it looks exactly like your triangle in the diagram but cut in half at 120

Math Is Fun Forum

#76 2012-11-01 10:30:57

Re: Circles: Chords, Radii, and Arcs

#77 2012-11-01 10:44:34

Re: Circles: Chords, Radii, and Arcs

#78 2012-11-01 11:10:25

Re: Circles: Chords, Radii, and Arcs

#79 2012-11-01 13:11:24

Re: Circles: Chords, Radii, and Arcs

#80 2012-11-01 20:11:43

Re: Circles: Chords, Radii, and Arcs

#81 2012-11-02 05:36:09

Re: Circles: Chords, Radii, and Arcs

#82 2012-11-02 09:54:14

Re: Circles: Chords, Radii, and Arcs

#83 2012-11-02 20:12:11

Re: Circles: Chords, Radii, and Arcs

#84 2012-11-03 10:09:44

Re: Circles: Chords, Radii, and Arcs

#85 2012-11-03 10:42:00

Re: Circles: Chords, Radii, and Arcs

#86 2012-11-03 11:46:23

Re: Circles: Chords, Radii, and Arcs

#87 2012-11-03 13:19:14

Re: Circles: Chords, Radii, and Arcs

#88 2012-11-03 13:21:28

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#89 2012-11-03 13:22:51

Re: Circles: Chords, Radii, and Arcs

#90 2012-11-03 20:23:39

Re: Circles: Chords, Radii, and Arcs

#91 2012-11-04 03:22:17

Re: Circles: Chords, Radii, and Arcs

#92 2012-11-04 04:09:47

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#93 2012-11-04 04:31:06

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#94 2012-11-04 04:59:57

Re: Circles: Chords, Radii, and Arcs

#95 2012-11-04 06:16:41

Re: Circles: Chords, Radii, and Arcs

#96 2012-11-04 06:27:22

Re: Circles: Chords, Radii, and Arcs

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Re: Circles: Chords, Radii, and Arcs

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Re: Circles: Chords, Radii, and Arcs

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Re: Circles: Chords, Radii, and Arcs

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