Math Is Fun Forum

helpmewithproofs

Member

Registered: 2013-08-15

Posts: 7

Geometry proof help

Can someone please help me do a 2 column proof similar to the one below with the given Triangle?

Photo of Triangle: http://i1039.photobucket.com/albums/a477/tricnetworks/IMG_11451.jpg

2 column proof as an example: http://www.wyzant.com/Images/Help/theorem_pf3.gif

Last edited by helpmewithproofs (2013-08-16 12:59:58)

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Geometry proof help

Hi;

It looks like we have AAS, which is marked on the diagram. So DG equals GF and you are done. Unless I am missing something.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Geometry proof help

Hi;

Just put the reason right next to it? Do you know the reasons?

1) Angle FEG = angle DEG : because EG bisects angle DEF.

2) Angle EDG = angle EFG : given

3) ΔGED is congruent to ΔGEF: AAS

4) DG = GF : CPCTE

5)ΔDGF is isosceles: Two sides are equal. Definition of an isosceles triangle.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,643

Re: Geometry proof help

The two column format is just a neat way to write down the proof.

You put down a statement about the question in the first column.

And the reason you know it is true in the next.

Everyone who has helped you with this question (in both posts) has given what you need for column one and column two.

Just to make it completely clear I have set out the first step in columns below.  Click the picture to see it full size.

Bob

Sorry.  got my letters wrong.  That should be GE not DE of course.

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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

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Geometry proof help

Did a computer write that?

Did they say my proof is wrong?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,643

Re: Geometry proof help

You will have to show us exactly what you submitted.

Bob

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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