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Review: Intersecting Lines Coplanar lines that share one common - - PowerPoint PPT Presentation
Review: Intersecting Lines Coplanar lines that share one common - - PowerPoint PPT Presentation
Review: Intersecting Lines Coplanar lines that share one common point. E Symbol: A D Example: AC BE at D. B C Lines that intersect to form right angles. A Symbol: ^ Example: B D BD ^ AC C Three or more lines that
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Three or more lines that intersect at the same point.
Example: AG, BF, and DH are concurrent lines and intersect at point K.
A B D F G H K
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Definition – coplanar lines that do not intersect
A B C D Symbol: //
Example: AB // CD
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Definition – noncoplanar
- lines. Therefore, they are
neither parallel, nor intersecting.
Example F C D B E A H G EG and AB are skew lines
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Definition – planes that do not intersect.
F C D B E A H G
Examples: GFDE and HCBA GHAE and DBCF
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Check for Understanding
F C D B E A H G
- 1. Two parallel lines.
- 2. Two parallel planes.
- 3. Two skew lines.
- 4. Two intersecting planes.
- 5. Two intersecting lines.
- 6. Three concurrent lines.
- 7. Four coplanar points.
- 8. Two perpendicular lines.
Figure is a cube. Name each figure using proper notation.
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Check for Understanding
- 1. ED DB
- 2. EDFG DFCB
- 3. Classify GE and DF.
- 4. Classify GE and DB.
- 5. Classify GE and EA.
- 6. Classify GE and BC.
F C D B E A H G
Figure is a cube.
Point D Parallel Skew Intersecting or Perpendicular Parallel DF
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Definition – a line that intersects two or more coplanar lines in different points.
Note: the “two or more coplanar lines” do NOT have to be parallel.
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When two lines cut by a transversal several pairs of angles are formed.
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Corresponding Angles
1 2
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Alternate Interior Angles
3 1
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Alternate Exterior Angles
5 4
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Same Side Interior Angles
6 1
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Same Side Exterior Angles
2 4
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