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Head First 2D Geometry
book

Head First 2D Geometry

by Stray (Lindsey Fallow), Dawn Griffiths
November 2009
Beginner content levelBeginner
368 pages
8h 55m
English
O'Reilly Media, Inc.
Content preview from Head First 2D Geometry
you are here 4 245
quadrilaterals
If you don’t like what you’re given, change it
True, geometry has lots of rules, but moving things around doesn’t mean you’re
breaking them. By moving the shapes you created in the parallelogram around,
you were able to form a rectangle. And you know that it has the same height and
same base width as the original parallelogram. So now…you know how to find
the area of a parallelogram!
Here’s a new parallelogram lawn you’ve been asked to mow. What
should you charge for mowing it?
Parallelogram Area = Base Width × Height
Look familiar? It’s the
same formula you’d use
to calculate the area
of a rectangle.
Width
Height
The dotted line shows
the shape of the
original parallelogram.
We moved the end triangle
to form a rectangle.
45 meters
16 meters
34 meters
246 Chapter 6
sharpen solution
Here’s a new parallelogram lawn you’ve been asked to mow. What
should you charge for mowing it?
Q:
What if I only have one pair
of opposite sides? Do I still have a
parallelogram?
A: No. In order for a shape to be a
parallelogram, both pairs of opposite sides
must be parallel. If you only have one pair
of opposite parallel sides, your shape isn’t a
parallelogram.
Q:
Can I still use the same formula
for finding the area for that shape?
A: This formula is specific to
parallelograms. ...
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Publisher Resources

ISBN: 9780596808365Errata Page