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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
14 Chapter 1
lining up
81º
If we had a pair of right angles, they would add
up to 90º + 90º = 180º.
Our pair of mystery angles make up the same
total angle as a pair of right angles, so
aº + bº = 180º.
Angles on a straight line add up to 180º
Whether a half turn is made up of two quarter turns or
lots of different small turns, the total angle of a half turn
is always 180º.
This means that when the angle on a straight line is
divided up into smaller angles we can always be sure that
they add up to 180º.
Half a pizza is half
a pizza, no matter
how you slice it.
We know that you can always fit a pair of right angles on a
straight line, but what if we don’t have right angles?
What might this pair of mystery angles (a and b) from our
crime scene sketch add up to?
81º
90º + 9º + 81º = 180º
Solution
you are here 4 15
finding missing angles
Angle Magnets
Fit the loose angle magnets into the gaps to form three complete
straight lines. Some gaps might need more than one magnet to fill them.
60º
64º
48º
Here
Here
Here
55º
14º
132º
80º
65º
22º
You might need to try a
few different combinations,
so don’t be shy!
16 Chapter 1
angle magnets solution
Angle Magnets Solution
Fit the loose angle magnets into the ...
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Publisher Resources

ISBN: 9780596808365Errata Page