Geometry: An Interactive Journey to Mastery



Lesson 3: Angles and Pencil-Turning Mysteries

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   ͼ௘6HHFigure 3.10௘ͽ
   *LYHQ x and yDUHFRPSOHPHQWDU\
   ORAOS.
   Prove: ‘#‘xz.
   Proof
   i. xy = EHFDXVHRIWKHGH¿QLWLRQRI³FRPSOHPHQWDU\ ́
   ii. yz = EHFDXVH.
   LLL 6R.


9. )LQGWKHPHDVXUHRIxͼ௘6HHFigure 3.11௘ͽ


10. 'HVSLWHEHLQJGUDZQRQWKHSDJHHVWDEOLVKWKDW
    WKHIROORZLQJ¿JXUHGRHVQRWDFWXDOO\H[LVW
    ͼ௘LQÀDWJHRPHWU\DWOHDVW௘ͽͼ௘6HHFigure 3.12௘ͽ

2 x

x

x

x

x + 10

Figure 3.11

x

x

x x

x

x

x

x

Figure 3.12

ES

z

x

y

O

R

Figure 3.10