You can put this solution on YOUR website! Rectangle have 4 sides.
Triangles have 3 sides.
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There really is no relationship between them... although they used to go out back in freshman year. The triangle thought the rectangle was getting too square and the rectangle thought the triangle would be cuter with that extra side.
You can put this solution on YOUR website! I believe that you can find the answer at
http://www.regentsprep.org/Regents/math/geometry/math-GEOMETRY.htm