1. Properties of Quadrilaterals

2. Quadrilaterals Two-dimensional, closed shape
Four straight sides and four angles
Sum of angles: 360⁰
Diagonals AC, BD
Line segment from one vertex to the opposite vertex
Seven types of quadrilaterals

3. Parallelogram Opposite sides are parallel & equal
Opposite angles are equal

4. Types of Parallelograms
Rectangle
Square
Rhombus
Parallelogram
All angles are 90⁰
Parallelogram
All angles are 90⁰
All sides are equal in length
Parallelogram
Opposite angles are equal, do not have to be 90⁰
All sides are equal in length

5. Trapezoid One pair of opposite sides are parallel
A “regular” trapezoid:
non-parallel sides ARE equal
base angles are equal
Regular trapezoid

7. Other Quadrilaterals Irregular quadrilaterals Kite No specifications
Two pairs of adjacent sides are equal in length
One pair of opposite angles (the ones that are between the sides of unequal length) are equal in size.
One diagonal bisects the other.
Diagonals intersect at right angles.

8. Area of Quadrilaterals
Area is measured in square units
Number of squares required to cover the surface
Be consistent with units
Example: If a rectangle is 6 inches wide and 4 feet long, what is the area?
Solution: Must convert units to make both measurements consistent. 6 inches = ½ feet
½ ft x 4 ft = 2 ft²
Area = 2 ft²

9. Area of Quadrilaterals
Type of Quadrilateral
Area Formula
Parallelogram
A = bh
Rectangle
Square
A = s²
Rhombus
A = bh or (1/2)d1*d2
Trapezoid
A = (1/2)h(b1 + b2)
Kite
A = (1/2)(d1*d2)
Irregular
Break into parts & add
Key:
b – base
h – height
s – side
b1/b2 – base1/base2
d1/d2 – diagonal1/diagonal2