A Guide to the GRE/Quadrilaterals

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The angles of a quadrilateral add up to 360º. There are 6 key types:

Square Rectangle
Four equal, 90º angles
Four equal sides
Rhombus Parallelogram
Opposing sides are parallel
Diagonal angles are equal
Adjacent angles add up to 180º
All four sides are equal


  • One set of parallel sides


  • Two sets of adjacent equal sides