# 10-3_Area of Parallelograms by dandanhuanghuang

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```									                   10:3 Area of
Parallelograms
Objective: Find the area of parallelograms
and composite figures
Standard: G4.2 Carry out a procedure to find the area of
quadrilaterals, regular polygons, and composite figures.

RELEVENCE: Area of parallelograms is used in construction and
interior design.

PRIOR LEARNING: Area of basic figures is learned in elementary school.
Perimeter of Squares &
Rectangles
 Square
EXAMPLE: Find the perimeter.
P   = 4s
 Rectangle
20cm
 P = 2l + 2w
 P – Perimeter   14cm
12cm
 s – side
 l – length
 w – width
Area of Square & Rectangle
 Square
EXAMPLE: Find the area.
A   = s2
 Rectangle
20cm
A = l ◦ w
 A – area     14cm
12cm
 s – side
 l – length
 w – width
Base:
 ANY side of a parallelogram can be called
a base

 For each base, there is a corresponding
altitude
Altitude:
A corresponding altitude is any segment
perpendicular to the base

 Thelength of an altitude is called the
height of the parallelogram
Perimeter of Parallelograms:
EXAMPLE: Find the perimeter.
(do not use height)

P   – perimeter                  14cm      20cm

12cm
Area of Parallelograms:
A   = bh
EXAMPLE: Find the area.

A  – area
 b – base                 14cm      20cm

 h - height
12cm
Postulate:
 Thearea of a region is the sum of the
areas of all of its non-overlapping parts.
Example 1:
 Find    the area of the figure.
7 ft

12 ft

5 ft

17 ft
Example 2:
 Find   the area of the figure.
9 cm
3 cm

7 cm
9 cm
4 cm

13 cm
Example 3: Real-world
Application
   Taylor’s grandparents
are moving into a
retirement home.                               Bedroom
Bath    2
Before they move in,            Bedroom
12 ft
17 ft
1
they want to recarpet   20 ft
5 ft      Hall
the two bedrooms                                 20 ft
and hall. Find the               14 ft
amount of carpeting
needed to cover this
floor space.
 Find   the area of each figure.
1.      4mm                 2.                   15 in.

6 in.

8mm                                                                5 in.
6mm
6 in.                             2 in.
16 in.
10mm
A – B Pair Share
1.   Person “A” works the first problem while
person “B” observes and coaches when
necessary.
2.   When “A” finishes, “B” is to initial the
problem to show agreement with the
results.
3.   “A” and “B” switch roles and repeat steps
1 and 2.
EXIT TICKET