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October 12th, 2008, 04:47 AM
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| | triangle divided into isosceles triangles Hi, can any triangle be divided into isosceles triangles? How to prove or disprove that? Thanks a lot. | 
October 12th, 2008, 05:18 AM
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| | Hello, Quote:
Originally Posted by disclaimer Hi, can any triangle be divided into isosceles triangles? How to prove or disprove that? Thanks a lot. | What do you think about considering the circumscribed circle ?
Let ABC be the triangle and O be the center of this circle.
OA=OB=OC.
So it may be interesting to see the properties of triangles OAB, OAC and OBC
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October 12th, 2008, 06:01 AM
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| | Ah, right, silly me.
Moo, I see that you've posted A LOT since my last visit here.
Thanks. | 
October 12th, 2008, 06:13 AM
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| | Quote:
Originally Posted by disclaimer Hi, can any triangle be divided into isosceles triangles? How to prove or disprove that? Thanks a lot. | In my opinion this is only possible if the triangle doesn't contain an obtuse interior angle.
Then the center of the circumscribed circle is outside the triangle and at least 2 of the radii are placed outside the triangle too. | | The following users thank earboth for this useful post: | |  | 
October 12th, 2008, 06:22 AM
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Originally Posted by earboth In my opinion this is only possible if the triangle doesn't contain an obtuse interior angle.
Then the center of the circumscribed circle is outside the triangle and at least 2 of the radii are placed outside the triangle too. | I see your point here. But still, maybe there's a different way of proving that property for an obtuse-angled triangle? | 
October 12th, 2008, 12:12 PM
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| | LoL, I think I got it.
You can always inscribe a circle in a triangle. Then, connecting the points of tangency with the sides of the triangle to the center of the circle and drawing another triangle whose vertices are also those tangency points, we obtain six isosceles triangles within the original one.
Don't you guys think so? | | The Following 2 Users Say Thank You to disclaimer For This Useful Post: | |  | 
October 12th, 2008, 12:28 PM
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| | Quote:
Originally Posted by disclaimer LoL, I think I got it.
You can always inscribe a circle in a triangle. Then, connecting the points of tangency with the sides of the triangle to the center of the circle and drawing another triangle whose vertices are also those tangency points, we obtain six isosceles triangles within the original one.
Don't you guys think so?  | Good spot !
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