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#1 2013-12-30 02:41:15

bobbym
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From: Bumpkinland
Registered: 2009-04-12
Posts: 81,665

An inscribed isosceles triangle with geogebra.

If an isosceles triangle PQR, in which PQ=PR=12 cm, is inscribed in a circle of radius 18 cm, find the area of the triangle

1) Use the circle tool to create a circle with a radius of 18.

2) Put point P on the circle.

3) Draw a circle with radius 12 using P as the center.

4) Use the intersection tool to find the 2 intersections of the 2 circles, Label them Q and R.

5) Hide the smaller circle and use the polygon tool to create the triangle with P,Q and R as vertices.

6) Read off the value of poly1 and take it over to the ISC.

http://isc.carma.newcastle.edu.au/

there using the super techniques of experimental mathematics they will guess at a nice analytical form for all those digits.

7) Read off

this agrees with the analytical answer nicely.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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#2 2013-12-31 06:35:39

Agnishom
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From: The Complex Plane
Registered: 2011-01-29
Posts: 14,350
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Re: An inscribed isosceles triangle with geogebra.

Hmm


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

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#3 2013-12-31 06:43:46

bobbym
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From: Bumpkinland
Registered: 2009-04-12
Posts: 81,665

Re: An inscribed isosceles triangle with geogebra.

Did you try this?


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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#4 2013-12-31 06:46:25

Agnishom
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From: The Complex Plane
Registered: 2011-01-29
Posts: 14,350
Website

Re: An inscribed isosceles triangle with geogebra.

No, how does geogebra get the area?


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

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#5 2013-12-31 06:49:19

bobbym
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From: Bumpkinland
Registered: 2009-04-12
Posts: 81,665

Re: An inscribed isosceles triangle with geogebra.

There are many ways to get the area of a triangle knowing 3 points.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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#6 2013-12-31 06:50:53

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 14,350
Website

Re: An inscribed isosceles triangle with geogebra.

Oh, I remember. I have a formula.

Yes, I did this but using pen and paper rather than a maxhine


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

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#7 2013-12-31 07:17:24

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 81,665

Re: An inscribed isosceles triangle with geogebra.

Then I suggest you try post #1 to see how it works.

Yes, I did this but using pen and paper rather than a maxhine

Yikes!


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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#8 2013-12-31 07:19:26

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 14,350
Website

Re: An inscribed isosceles triangle with geogebra.

Why is it different?


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

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#9 2013-12-31 07:30:25

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 81,665

Re: An inscribed isosceles triangle with geogebra.

Better than me trying to explain in my words why not listen to the experts who understand it better.

http://www.mathisfunforum.com/viewtopic … 06#p266506

After you read all of that it should be clearer.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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#10 2013-12-31 10:22:59

Nehushtan
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From: London
Registered: 2013-03-09
Posts: 606
Website

Re: An inscribed isosceles triangle with geogebra.

bobbym wrote:

There are many ways to get the area of a triangle knowing 3 points.

Yup.

http://www.mathopenref.com/coordtrianglearea.html


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#11 2013-12-31 23:43:35

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 14,350
Website

Re: An inscribed isosceles triangle with geogebra.

bobbym wrote:

Better than me trying to explain in my words why not listen to the experts who understand it better.

http://www.mathisfunforum.com/viewtopic … 06#p266506

After you read all of that it should be clearer.

Who is the expert there?

When I did it using coordinate geometry, I'm also using the same method as Geogebra will. Why is that any different?


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

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#12 2013-12-31 23:48:13

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 81,665

Re: An inscribed isosceles triangle with geogebra.

Did you check my solution? I would not have got the idea without geogebra. These babies can also give you insight on how to do it with pencil and paper.

Who is the expert there?

Some mathematician, I failed to include the name. More importantly did you read it?


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

Offline

#13 2013-12-31 23:53:04

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 14,350
Website

Re: An inscribed isosceles triangle with geogebra.

Yes, it is your solution that I did on pen and paper. Why do you still want me to do the same method on a computer again?


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

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#14 2013-12-31 23:57:43

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 81,665

Re: An inscribed isosceles triangle with geogebra.

Not again, first!


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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#15 2014-01-01 00:48:19

Agnishom
Real Member
From: The Complex Plane
Registered: 2011-01-29
Posts: 14,350
Website

Re: An inscribed isosceles triangle with geogebra.

I beg your pardon?


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'Humanity is still kept intact. It remains within.' -Alokananda

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#16 2014-01-01 00:57:17

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 81,665

Re: An inscribed isosceles triangle with geogebra.

Why do you still want me to do the same method on a computer again?

I was saying the problem should be done first on the computer.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

Offline

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