GMAT Quantitative Review
3.0 Math Review
A polygon with four sides is a quadrilateral. A quadrilateral in which both pairs of opposite sides are parallel is a parallelogram. The opposite sides of a parallelogram also have equal length.
In parallelogram JKLM, and ; and .
The diagonals of a parallelogram bisect each other (that is, and ).
The area of a parallelogram is equal to
The area of JKLM is equal to .
A parallelogram with right angles is a rectangle, and a rectangle with all sides of equal length is a square.
The perimeter of and the area of WXYZ is equal to .
The diagonals of a rectangle are equal; therefore .
A quadrilateral with two sides that are parallel, as shown above, is a trapezoid. The area of trapezoid PQRS may be calculated as follows: