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#1 2012-09-07 21:03:01
A few simple proofs about Triangles
Let there be a triangle ABC and O a point inside it.
Now, how can I prove that:
1.
2.
Last edited by Agnishom (2012-09-07 21:04:17)
'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'
I'm not crazy, my mother had me tested.
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#2 2012-09-07 22:59:19
- Bob
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- Registered: 2010-06-20
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Re: A few simple proofs about Triangles
hi Agnishom
Here's a start for number 2.
AO + OB > AB
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob 
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#3 2012-09-08 00:15:42
Re: A few simple proofs about Triangles
I did 2.
Adding all those,
'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'
I'm not crazy, my mother had me tested.
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#4 2012-09-08 00:28:22
- Bob
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- Registered: 2010-06-20
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Re: A few simple proofs about Triangles
Excellent!
I am hoping there's a similar way to do Q1 but, so far, it has eluded me.
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob
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#5 2012-09-08 00:37:29
Re: A few simple proofs about Triangles
I remember doing it at the 7th Grade, but what about 1.?
'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'
I'm not crazy, my mother had me tested.
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#6 2012-09-08 01:27:25
- noemi
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- Registered: 2010-01-07
- Posts: 2,333
Re: A few simple proofs about Triangles
Hint for 1.:
OA+OB<CA+CB
Last edited by noemi (2012-09-08 01:29:34)
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#7 2012-09-08 03:55:11
Re: A few simple proofs about Triangles
Hint for 1.:
OA+OB<CA+CB
Why?
'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'
I'm not crazy, my mother had me tested.
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#8 2012-09-08 03:56:12
Re: A few simple proofs about Triangles
Please somebody help me!
'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'
I'm not crazy, my mother had me tested.
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#9 2012-09-08 04:23:50
- noemi
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- Registered: 2010-01-07
- Posts: 2,333
Re: A few simple proofs about Triangles
OA+OB<CA+CB
OB+OC<AB+AC
OC+OA<BC+BA
adding all those you get what you need, assuming CA=AC etc.
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#10 2012-09-08 13:59:03
Re: A few simple proofs about Triangles
Hmmmmmm..................
That set of problem had another problem which I shall be posting in a new thread
'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'
I'm not crazy, my mother had me tested.
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