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 intersect at the same point. D A F Example: K B AG, BF, and DH are G H concurrent lines and intersect at point K.

Definition – coplanar lines that do not intersect Symbol: // B D Example: A C AB // CD

Example Definition – noncoplanar lines. Therefore, they are neither parallel, nor G F intersecting. E D EG and AB are skew lines H C A B

Definition – planes that do not intersect. G F E Examples: D GFDE and HCBA H GHAE and DBCF C A B

Check for Understanding G F 1. Two parallel lines. E D 2. Two parallel planes. H C 3. Two skew lines. A B 4. Two intersecting planes. Figure is a cube. 5. Two intersecting lines. 6. Three concurrent lines. Name each figure using 7. Four coplanar points. proper notation. 8. Two perpendicular lines.

G Check for Understanding F 1. ED  DB Point D E D 2. EDFG  DFCB DF H C 3. Classify GE and DF. Parallel A B Figure is a cube. Skew 4. Classify GE and DB. 5. Classify GE and EA. Intersecting or Perpendicular Parallel 6. Classify GE and BC.

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.

When two lines cut by a transversal several pairs of angles are formed.

2 1 Corresponding Angles

3 1 Alternate Interior Angles

5 4 Alternate Exterior Angles

6 1 Same Side Interior Angles

2 4 Same Side Exterior Angles

5 2 3 6 7 1 8 4