Multi-Part Lesson
8-3
PART
Main Idea
I will explore area.
Area of Composite Shapes
A
B
C
Use Models to Find Areas
of Composite Shapes
Area is measured in square units. You have used squares to find
the area of rectangles and squares. You can also find the area of
other shapes.
macmillanmh.com
Find the area of the shaded region.
One Way
Step 1
Count the square units.
The shape shows that
there are 48 square units.
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Another Way
Step 1
Decompose the shape
into rectangles and squares.
The shape can be broken
into two rectangles and
one square.
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Step 2
Find the area of the parts. Then add them
together.
3 × 5 = 15
3×3=9
6 × 4 = 24
15 + 24 + 9 = 48
So, the area of the shape is 48 square units.
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Chapter 8 Find Area
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About It
1. How else could you decompose the shape into rectangles?
2. How would that affect the area?
3. Why is it helpful to decompose shapes into rectangles?
4. On a piece of grid paper, shade in squares to make a picture. Find
the area of the shape.
5. Why is the area of the shape in the activity labeled
square units?
and Apply It
Find the area of each shape.
6.
7.
8.
10.
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area? Explain.
9.
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Which two exercises above have the same
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Lesson 8-3 Area of Composite Shapes
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