Fundamentals of Math

Fundamentals of Mathematics

Perimeter of Quadrilaterals Like triangles, to find the perimeter of any quadrilateral take the sum of the side lengths.

Example 5.4.1

= ̅̅̅̅ + ̅̅̅̅ + ̅̅̅̅ + ̅̅̅̅

= 1.6 in. + 3.6 in. + 2.5 in. + 4.5 in.

= 12.2 in.

Area of Quadrilaterals The area of quadrilaterals is a bit trickier as the formula changes depending on the type of quadrilateral. All parallelograms (parallelograms, rectangles, rhombuses, and squares) have an area of length × width (or base × height - we use the terms interchangeably). The area of a trapezoid (regular or isosceles) is 1 2 ℎ( 1 + 2 ) , and the area of a kite is 1 2 ( 1 × 2 ) .

Area Formulas for Quadrilaterals

Parallelogram

Rectangle

Rhombus

Square

ℎ × ℎ

ℎ × ℎ

× ℎ ℎ

ℎ × ℎ

Trapezoid

Isosceles Trapezoid

Kite

1 2

1 2

1 2

ℎ(

+

)

ℎ(

+

)

(

×

)

1

2

1

2

1

2

Example 5.4.2

Find the area of the kite of ̅̅̅̅ = 49.5 ft and ̅̅̅̅ = 60 ft.

= 1 2

( 1

)

× 2

1 2 (49.5 ft × 60 ft) =

1 2 (2970 ft 2 ) = 1485 ft 2

=

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