3.1 Lines and Angles

Skew Lines – lines that do not intersect are not parallel or coplanar. Parallel Lines – two lines that are coplanar and do not intersect. Notation: // Skew Lines – lines that do not intersect are not parallel or coplanar. Parallel Planes – two planes that do not intersect.

Identifying Nonintersecting Lines and Planes Which segments are parallel to AD? Which segments are skew to GH? What are two pairs of parallel planes? What are two segments parallel to plane DCGH?

Rally Robin

TRANSVERSAL – a line that intersects two or more coplanar lines at different points. 1 2 3 4 5 6 7 8 Notice, angles 3, 4, 5, and 6 are interior angles (between the lines). Angles 1, 2, 7, and 8 are exterior angles (outside the lines).

CORRESPONDING ANGLES: occupy corresponding positions 1 2 3 4 6 5 7 8 Corresponding angles lie on the same side of the transversal, and in corresponding positions

ALTERNATE EXTERIOR ANGLES: lie outside the two lines on opposite sides of the transversal. 1 2 3 4 5 6 7 8

ALTERNATE INTERIOR ANGLES: lie between the two lines on opposite sides of the transversal. 1 2 3 4 5 6 7 8

SAME-SIDE (CONSECUTIVE) INTERIOR ANGLES: lie between the two lines on the same side of the transversal. l 3 5 1 2 4 6 7 8

Identifying an Angle Pair Name a pair of alternate interior angles. Name a pair of consecutive interior angles. Name a pair of corresponding angles. Name a pair of alternate exterior angles.

Rally Robin Name two pairs of alternate interior angles. Name two pairs of consecutive interior angles. Name two pairs of corresponding angles. Name two pairs of alternate exterior angles.

Checkpoint: Corresponding? Alternate exterior? Alternate interior? 4 3 8 Alternate interior? 2 7 1 6 5 Same Side Interior? Vertical Angles? Linear Pairs?

Name one pair of each of the segments, planes, or angles Parallel segments Skew segments Parallel planes Alternate interior Same-side interior Corresponding Alternate exterior Vertical Linear Pair

HOMEWORK p.144 #17-42 all,