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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 21
finding missing angles
Find one more angle to crack the case
There’s only one unknown angle left on the diagram. Once you’ve
figured out this one you can charge Benny with the shooting for sure.
Find this last mystery angle to complete your investigation
and prove that Benny was the shooter.
How does it fit in with what you’ve already found out?
BULLET
PATH
MICKY
BENNY
FOOTPRINTS
18º
CRIME SCENE SKETCH
CASE GEO180
(ANGLES AS MEASURED
BUT DRAWING NOT TO
SCALE)
81º
86º
72º
81º 99º
22 Chapter 1
something funny is going on…
Find this last mystery angle to complete your investigation and
prove that Benny was the shooter.
How does it fit in with what you’ve already found out?
BULLET
PATH
MICKY
BENNY
FOOTPRINTS
18º
CRIME SCENE SKETCH
CASE GEO180
(ANGLES AS MEASURED
BUT DRAWING NOT TO
SCALE)
81º
86º
72º
81º 99º
There are 2 different ways to find this
mystery angle—you might have done either one.
1)
2)
Angle c is opposite
this angle here
And vertical angles are equal,
so ? = 18º
Angles in a triangle add up to 180º
so 81º + 86º + ? = 180º
? = 180º - 81º - 86º = 13º
Hmm…something funny
is going on. It doesn’t
matter how you worded
it,.as long as you noticed
something didn’t add up.
But this doesn’t fit with the
triangle angles:
18º + 81º + 86º = 185º
They should add up to 180º.
But this doesn’t fit ...
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Publisher Resources

ISBN: 9780596808365Errata Page