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## #1 2012-10-29 08:30:15

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Circles: Chords, Radii, and Arcs

Hi everybody!

I need help seeing if I answered the following questions correctly

(The Image the questions are talking about is below)

#1- I choose A

1. If the diameter of circle M is 20, and the length of line segment DF is 12, what is the length of segment MJ?
A 6
B 45
C 4
D 8
E 17
F 3

#2- I choose B

2. If the measure of arc BFE is 80 degrees, then what is the measure of angle BME?
A 37 deg
B 80 deg
C 9 deg
D 23 deg
E 17 deg
F 41 deg

#3 I choose F

3. If there were an imaginary angle ACB, what would the measure of that angle be? (Hint: Remember that a line is an angle with a measure of 180 degrees, or that a circle has a total arc measure of 360 degrees.)
A 45 deg
B 19 deg
C 30 deg
D 60 deg
E 27 deg
F 90 deg

Thanks

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #2 2012-10-29 09:45:47

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,389

### Re: Circles: Chords, Radii, and Arcs

Hi zee-f;

For 1) I have D.

For 2) I agree.

For 3) I agree.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #3 2012-10-29 10:08:20

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

I agree that #1 is D but I was stuck between subtracting or just or dividing the 12

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #4 2012-10-29 10:09:25

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

#4- I choose E

4. If angle EMA has a measure of 100 degrees, what is the measure of arc EDA?
A 77 deg
B 180 deg
C 15 deg
D 26 deg
E 100 deg
F 164 deg

#5- I choose E

5. If I had an imaginary line from M to H, with a length of 15, and told you that line segment HI had a length of 9, what would the radius of circle M be?
A 12
B 9
C 18
D 17
E 15
F 24

#6- I choose E

6. Imagine there is a line segment AD, and a line segment BF. If the measure of angle DAB is 60 degrees, what is the measure of angle DFB?
A 54 deg
B 167 deg
C 135 deg
D 175 deg
E 30 deg
F 120 deg

#7- I choose D

7. If angle EMA is 95 degrees, what is the measure of angle BME?
A 85 deg
B 25 deg
C 56 deg
D 34 deg
E 75 deg
F  46 deg

#8- I choose B

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
B sqrt 2
C sqrt 8
D sqrt 13
E sqrt 4
F sqrt 3

9- I choose A.

9. If the diameter of circle M is 12, what would the length of MI be?
A 12
B 8
C 27
D 6
E 2
F 9

#10- I choose D

10. If imaginary triangle DJE were a 30-60-90 triangle, with angle EDJ as the 30 degree angle, and chord DF had a length of 18, what would the length of line segment DE be?
A 5
B 6
C 27
D 6*sqrt(3)
E 10
F 12

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #5 2012-10-29 10:15:59

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,389

### Re: Circles: Chords, Radii, and Arcs

Hi;

I used Pythagoras there.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #6 2012-10-29 11:11:16

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

Isn't line segment DJ  half of DF. So since line segment DF= 12  line segment DJ= 6 ?

So you used the sides of 6 and the hypoteneuse of 20
6^2 + b^2 = 20^2 ?????

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #7 2012-10-29 11:13:29

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,389

### Re: Circles: Chords, Radii, and Arcs

6^2 + b^2 = 10^2

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #8 2012-10-29 11:25:09

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

That is what I get

a^2 + b^2 = c^2

6^2 + b^2 = 10^2

Then we simplify:

36 + b^2 = 20

Then we solve for b:

b^2 = 20 - 36

b^2 = -16

Take the square root of both sides:

SQRT b^2 = SQRT -16

b = -4

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #9 2012-10-29 11:26:30

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,389

### Re: Circles: Chords, Radii, and Arcs

Hi;

36 + b^2 = 20

10^2 is not 20.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

Online

## #10 2012-10-29 11:33:33

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

but why did you use 10^2 ?
I am getting really confused for some reason I mean everything was clear when I read the lesson but some problems really confuse the whole thing

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #11 2012-10-29 11:35:19

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

ooooooh since we divided the 12 by half the 20 by half to I get it now

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #12 2012-10-29 11:37:20

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,389

### Re: Circles: Chords, Radii, and Arcs

The radius is half the diameter, so side MD is 10. This is the hypotenuse of right triangle.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

Online

## #13 2012-10-29 11:40:37

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

Thanks bobbym for all the help

(Talking about the same picture) I also really need help checking my answers on these

#4- I choose E

4. If angle EMA has a measure of 100 degrees, what is the measure of arc EDA?
A 77 deg
B 180 deg
C 15 deg
D 26 deg
E 100 deg
F 164 deg

#5- I choose E

5. If I had an imaginary line from M to H, with a length of 15, and told you that line segment HI had a length of 9, what would the radius of circle M be?
A 12
B 9
C 18
D 17
E 15
F 24

#6- I choose E

6. Imagine there is a line segment AD, and a line segment BF. If the measure of angle DAB is 60 degrees, what is the measure of angle DFB?
A 54 deg
B 167 deg
C 135 deg
D 175 deg
E 30 deg
F 120 deg

#7- I choose D

7. If angle EMA is 95 degrees, what is the measure of angle BME?
A 85 deg
B 25 deg
C 56 deg
D 34 deg
E 75 deg
F  46 deg

#8- I choose B

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
B sqrt 2
C sqrt 8
D sqrt 13
E sqrt 4
F sqrt 3

9- I choose A.

9. If the diameter of circle M is 12, what would the length of MI be?
A 12
B 8
C 27
D 6
E 2
F 9

#10- I choose D

10. If imaginary triangle DJE were a 30-60-90 triangle, with angle EDJ as the 30 degree angle, and chord DF had a length of 18, what would the length of line segment DE be?
A 5
B 6
C 27
D 6*sqrt(3)
E 10
F 12

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #14 2012-10-29 11:45:35

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,389

### Re: Circles: Chords, Radii, and Arcs

Hi;

4) E , I agree.

Let's stop right here.

5) Your answer of 15 is impossible. The hypotenuse is 15 and it is always the longest side of a right triangle. Please try again.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

Online

## #15 2012-10-29 12:27:01

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

18 *1/2 = 9 So the answer would be 9

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #16 2012-10-29 12:30:35

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,389

### Re: Circles: Chords, Radii, and Arcs

How long is IH?

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

Online

## #17 2012-10-29 12:40:38

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

IH=9

oh so
15^2 - 9^2 = 225- 81=144

√144 = 12

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #18 2012-10-29 12:43:40

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,389

### Re: Circles: Chords, Radii, and Arcs

That is correct!

For 6) I am getting F.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

Online

## #19 2012-10-29 13:25:46

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

Thanks for all the help am going to take a rest a little been sitting on the computer for like more than 3 hours

Thank you so so much for all the help really appreciate  it

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #20 2012-10-29 13:26:54

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

I will review #6-#10 tomorrow

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #21 2012-10-29 13:27:12

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,389

### Re: Circles: Chords, Radii, and Arcs

Hi;

Did you check number 6?

Then get some rest. See you tomorrow.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #22 2012-10-30 01:37:30

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

Hi,

#6-  Imagine there is a line segment AD, and a line segment BF. If the measure of angle DAB is 60 degrees, what is the measure of angle DFB?

#6-
A 54 deg
B 167 deg
C 135 deg
D 175 deg
E 30 deg
F 120 deg

I agree that it is 120 deg because The measure of an inscribed angle is equal to one-half the degree measure of its intercepted arc.  So since I know that angle angle DAB has a measure of 60 degrees, I can know that arc fb must have a measure of 120 degrees, and the measure of a angle is equal to the length of the arc it defines. So the arc is 120 degrees  So the measure of angle DFB is 120 deg

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #23 2012-10-30 02:00:37

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,389

### Re: Circles: Chords, Radii, and Arcs

Hi;

Okay then I am getting 7 A.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

Online

## #24 2012-10-30 03:27:48

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

Did you subtract 180-95 and got 85 so that is the answer ?

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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## #25 2012-10-30 03:35:44

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

### Re: Circles: Chords, Radii, and Arcs

I like my answer on #8 but

9- I choose D.

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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