3.1 Lines and Angles

Parallel Lines (//)- coplanar lines that never intersect

Perpendicular Lines (┴)- intersect to form right angles.

Skew Lines are NOT coplanar, are not parallel, and do not intersect.

Parallel planes- planes that do not intersect.

Name a pair of parallel lines. Name a pair of perpendicular lines Name a pair of skew lines. Name a pair of parallel planes.

How many lines are there parallel to l that go through the point?

How many lines are there perpendicular to l that go through the point?

Transversal Line- a line that crosses two or more lines Transversal Line- a line that crosses two or more lines. When it crosses two lines it forms 8 angles. 1 2 3 4 5 6 7 8

Corresponding Angles- angles that lie on the same side of the transversal and on the same place on the other two lines (for example top left, top left) 1 2 3 4 5 6 7 8

Alternate Interior Angles- non-adjacent angles that lie on opposite side of the transversal and between the other two lines. 1 2 3 4 <3 & <6 <4 & <5 5 6 7 8

Alternate Exterior Angles- non-adjacent angles that lie on opposite side of the transversal and on the outside the other two lines. 1 2 3 4 <1 & <8 <2 & <7 5 6 7 8

Same Side Interior (consecutive interior)Angles- angles that lie on the same side of the transversal and on the inside the other two lines. 1 2 3 4 <3 & <5 <4 & <6 5 6 7 8