6.6 Special Quadrilaterals

ExampleQuad ABCD has at least one pair of

opp sides What kinds of quads could it be?

• Parallelogram

• Rhombus

• Rectangle

• Square

• Isosceles Trapezoid

ABCD has at least 2 consecutive sides, What quads

meet this condition?

• Square

• Kite

• Rhombus

The coordinates of ABCD are A(-2,5), B(1,8) C(4,5) D(1,2). Show

that ABCD is a rhombus.• 1 way: use Distance formula

• AB=

• BC=

• CD=

• DA=

1899)58()41( 22

1899)85()12( 22

1899)25()14( 22

1899)52())2(1( 22 All four sides , so it is a rhombus.

Example cont.

• Another way: use Slope Formula• m of seg AB=

• m of seg CD=

• m of seg BC=

• m of seg DA =

13

3

)2(1

58

13

3

14

25

13

3

41

58

13

3

)2(1

52

Opp sides are ll, so it is a parallelogram. Now show that the diags are to prove it’s a rhombus.

Example cont.

• Check slope of diags.

• m of seg AC=

• m of seg BD =

06

0

42

55

.0

6

11

28undef

Diagonals are , so it’s a rhombus.

** This shape is also a square!