# Advanced proof of parallelograms having equal areas

• Mar 30th 2012, 08:25 AM
lamp23
Advanced proof of parallelograms having equal areas
SOLUTION FOUND. You can extend EF and CB until they intersect.
http://i900.photobucket.com/albums/ac204/lamp23/par.jpg
• Mar 30th 2012, 09:07 AM
HallsofIvy
Re: Advanced proof of parallelograms having equal areas
If all you are given is that ABCD and DEFG are parallelograms then you can't prove they have the same area- it's not true! It is not true that all parallelograms have the same area. What properties of ABCD and DEFG are you given that you haven't mentioned?
• Mar 30th 2012, 09:09 AM
emakarov
Re: Advanced proof of parallelograms having equal areas
Quote:

Originally Posted by HallsofIvy
What properties of ABCD and DEFG are you given that you haven't mentioned?

Well, the picture shows obviously that $A\in EF$ and $G\in CB$.