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Intersecting of 2 cirlces of equal diameter

10/03/2009 3:42 PM

If two circles, of equal diameter intersect at each other's center,what is the length of the arc formed beginining at the point where they first intersect, and ending at the next point of intersection, not the area, simply the length of the curved line is desired to be known.

Thanks

Stu

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#1

Re: Intersecting of 2 cirlces of equal diameter

10/03/2009 3:47 PM

Homework?

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#2

Re: Intersecting of 2 cirlces of equal diameter

10/03/2009 4:31 PM

If r is the radius, then the length of the arc is 4(pi)(r)/sqrt(3).

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#3

Re: Intersecting of 2 cirlces of equal diameter

10/03/2009 7:40 PM

Half of one circle's perimeter I'd say.

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#4

Re: Intersecting of 2 cirlces of equal diameter

10/03/2009 9:02 PM

The question doesn't make sense. What intersects with what?

do you mean that each circle's circumference passes through the center of the other?

Now that the centers are significant, do they count for the length of arc?

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#5

Re: Intersecting of 2 cirlces of equal diameter

10/03/2009 9:28 PM

If circles radius is = R

then arc length you ask for is = (2/3)*pi*R

If this is a homework problem, I sincerely hope your teacher makes you present a graphical proof and an explanation of HOW you arrived at the answer.

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#6

Re: Intersecting of 2 cirlces of equal diameter

10/04/2009 12:05 AM

Intersecting circles

Givens:

  1. The circles are of the same diameter.
  2. The edge of each circle intersects with the center of the other.

If you draw the proposed problem, you will see that the distance between the centers of the circles is the radius, R, of the circle. Further, the midpoint between the circle centers is R/2. As you can see, this sets up a trigonometric identity problem for which an answer is quite easy to procure.

x2 + 0.5R2 = R2

x2 = R2 - 0.5R2

x = Sqrt(R2 - 0.5R2)

But the distance between the intersection point of the circles is 2x.

Therefore, the calculation for the distance (D) between the intersection points is:

D = 2*Sqrt(R2 - 0.5R2)

As has been said, you must endeavor to solve these problems with the information you have been given in class. Nothing teaches better than the solution arrived at through blood, sweat and tears.

The fact that you posted your problem here, in it's original form, makes me believe that you are not really trying to learn, but just want to get through school. If this is the case, you'd better give up now. You will be overrun by those who truly want to understand math and science. If you do make it, I think you would find your place in management.

Mike

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#7
In reply to #6

Re: Intersecting of 2 cirlces of equal diameter

10/04/2009 12:35 AM

I believe you are correct for the distance between the 2 intersection points.

The straight line distance further simplifies to

D = sqrt(3)*R

However, I think the OP asked for the arc (curved) length?

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#8

Re: Intersecting of 2 cirlces of equal diameter

10/04/2009 2:33 AM

d= R/2

S = lenght of arc = 2*R Cos¯¹ d/R = 2R Cos ‾¹ 1/2 (in radians)

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#9

Re: Intersecting of 2 cirlces of equal diameter

10/04/2009 3:53 AM
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#11
In reply to #9

Re: Intersecting of 2 cirlces of equal diameter

10/04/2009 7:49 AM

I was too lazy to draw so I will aplaude(GA) your drafting abilities (becase, I am sure that I answered, first, the question).

It was a good answer, indeed.

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#10

Re: Intersecting of 2 cirlces of equal diameter

10/04/2009 4:43 AM

Thanks for all your help.This is not homework.I was just curious.I have grandkids in high school.

stu

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#12
In reply to #10

Re: Intersecting of 2 cirlces of equal diameter

10/04/2009 7:37 PM

Oh - I thought is was homework so I was lying.

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