Geometry Notes

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Geometry Notes

• Section 1-4
• 9/11/07

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What youll learn

• How to measure and classify angles.
• How to identify and use congruent angles and the
  bisector of an angle.

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Vocabulary Terms

• Degree
• Ray
• Opposite rays
• Angles
• Sides of an angle
• Vertex of an angle
• Interior and exterior of an angle
• Right angle, obtuse angle, acute angle
• Angle bisector

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Raya part of a line

• Draw it with a dot (the endpt) at one end and an
  arrow at the other

P

• Name it with the endpt and one other pt on the
  ray

Q

• Fact 2 opposite rays meet at their endpts and
  make a straight line
• Words/Symbols
• PQ

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Two noncollinear rays intersecting at their
endpts make an. . .

• Angle

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Angleformed by two noncollinear rays that share
a common endpt

• Draw it with arrows

• Name it by
• 3 noncollinear pts on the angle (vertex in
  middle)
• The vertex
• a number

A

• Words/Symbols
• ?ART
• ?R
• ?1

R
1
T
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• Facts
• the 2 rays are the sides
• the common endpt is the vertex
• angles are measured in degrees

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Everyone knows

• Right angles measure 90º
• Acute angles measure between 0º and 90º
• Obtuse angles measure between 90º and 180º

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Congruent Angles

• Remember congruent means same shape and size
• All angles have basically the same shape (two
  noncollinear rays connected at a common endpoint)
• To be congruent two angles must have the same
  measure.
• Congruent angles will have identical marks

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Congruent Angles have identical marks. . .
?1 ? ?2
1
2
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Angle Bisectors-- rays that cut an angle into two
smaller congruent angles
A

• Draw it

T
B
C
BT bisects ?ABC so ?ABT? ?TBC
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Have you learned?

• How to measure and classify angles.
• How to identify and use congruent angles and the
  bisector of an angle.
• P. 34(13-47odd, 51-65odd)