conjecture

1
conjecture
1.1/1.2 Voc. And Notes
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• An unproven statement that is based on
  observations.

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• inductive reasoning

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• a process that involves looking for patterns and
  making conjectures

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• counterexample

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• an example that shows a conjecture is false

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• point

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• has no dimension, is represented by a small dot

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• line

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• has one dimension, extends in both directions

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• plane

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• has two dimensions, a flat surface that extends

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• collinear points

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• points that lie on the same line

C
B
A
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• coplaner points

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• points that lie on the same plane

points A,B,C are coplaner points D,C,B are
coplaner points D,C, A are coplaner points
D,C,B,A are not coplaner
B
C
D
A
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• line segment

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• Consists of endpoints A and B and all points on
  the line AB that are between A and B.

B
A
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• ray

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• Consists of the initial point A and all points
  on line AB that lie on the same side of A as B.

B
A
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• opposite rays

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• If A, B, and C are collinear and C is between A
  and B, then ray CA and ray CB are opposite rays.

C
A
B
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• congruent
• segments

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• segments that have the same length

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• midpoint

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• The point that divides or bisects a segment into
  two congruent segments.

A
B
C
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• Which points are coplaner and which are
  noncoplaner?

E
F
C
D
G
A
B
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• Draw four points J,K,L, and M, no three which are
  collinear. Then sketch ray JK, line segment KL,
  line LM and ray MJ.

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• M

J
K
L
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• postulate
• or
• axiom

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• rules that are accepted without proof

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• length

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• The distance between two points. Example the
  distance between point A and point B is
  represented by AB.

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• Segment Addition Postulate

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• If B is between A and C, then AB BC AC. If
  AB BC AC, the B is between A and C.

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Never assume B is the midpoint.
A
B
C
3. AB2x BC5x AC49
X?
2. AB10 AC40 BC?
1. AB7 BC20 AC?
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• 3. 2x 5x 49
• 7x 49
• X 7