
Parallelogram 
Rectangle 
If both pairs of opposite sides of a quadrilateral are congruent,
then the quadrilateral is a perallelogram. 
The diagonals of a rectangle are congruent 
.If both pairs of opposite angles of a quadrilateral are congruent,
then the quadrilateral is a parallelogram 
If the diagonals of a parallelogram are congruent,
then the parallelogram is a rectangle. 
If one pair of opposite sides of a quadrilateral is both parallel
and congruent,
then the quadrilateral is a parallelogram. 
If one angle of a parallelogram are is a right angle,
then the parallelogram is a rectangle. 
If the diagonals of a quadrialateral bisect each other,
then the quadrilateral is a parallelogram. 
The area of a rectangle is the product of the base and the height.
(A = bh) 
The area of a parallelogram is the product of the base and the
height.(A = bh) 

The opposite sides of a parallelogram are congruent. 
The opposite angles of a parallelogram are congruent. 
The diagonals of a parallelogram bisect each other. 
Trapezoid 
Rhombus and Square 
The area of a trapezoid is the product of the height and themean
of the bases. A
(A = 1/2 (b1 + b2)h) 
The diagonals of a rhombus are perpendicular. 
The base angles of an isosceles trapezoid are congruent. 
If the diagonals of a parallelogram are perpendicular,
then the parallelogram is a rhombus. 
If the base angles are congruent, then the trapezoid is isosceles. 
If two consecutive sides of a parallelogram are congruent
then the parallelogram is a rhombus. 
Kite 
The area of a square is the square of the length of one side.
(A = s2) 
Exactly one diagonal of a kite is a line of symmetry for the
kite and the perpendicular bisector of the other diagonal. 
