Special Parallelograms

Theorem 6-9

• Each diagonal of a rhombus bisects the opposite angles it connects

Theorem 6-10

• The diagonals of a rhombus are perpendicular

Area of a Rhombus

212

1ddA

Theorem 6-11

• The diagonals of a rectangle are congruent

Is the parallelogram a rhombus or a rectangle?

• If the diagonal bisects the opposite angles then it’s a rhombus

• If the diagonals are perpendicular then it’s a rhombus

• If the diagonals are congruent, then it’s a rectangle

Isosceles Trapezoid - Base angles

• The base angles are congruent to each other.

Isosceles Trapezoid

• The diagonals of an isosceles trapezoid are congruent

• Hint: Isosceles triangle has two equal sides and so the base angles should also be equal

Kite

• The diagonals of a kite are perpendicular• Hint: The t in kite crosses at a 90 degree angle,

so should the diagonals