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#1 2008-04-19 13:27:41
- stellina91
- Member
- Registered: 2008-04-15
- Posts: 12
Parallel Lines
Show that AB is not parallel to CD in the diagram, giving all reasons.
I am not certain of how I would set this out, could someone please help me?
Thank you.
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#2 2008-04-19 23:48:32
- mathsyperson
- Moderator
- Registered: 2005-06-22
- Posts: 4,900
Re: Parallel Lines
If the lines were parallel, then the two marked angles would equal each other (using the Z rule).
They don't, so the lines aren't parallel.
Why did the vector cross the road?
It wanted to be normal.
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#3 2008-04-21 06:47:28
- Hopecantid
- Member
- Registered: 2008-04-08
- Posts: 13
Re: Parallel Lines
Alternate interior angles between two parallel lines intersected by a transversal will be equal to each other. Since the two lines AB and CD do not have alternate interior angles equal to each other, they are not parallel.
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