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parallel lines

Two lines that are in the same plane but do not intersect

skew lines

Two lines that are not in the same plane and do not intersect

slope

The ratio of vertical change (rise) to horizontal change (run) between any two points on a nonvertical line

transversal

A line that intersects two or more coplanar lines at different points

slope-intercept form

The general form of a linear equation: y=mx+b

standard form

Ax + By=C where A and B are not both zero

corresponding angles

Two angles that are in the SAME CORNER or CORRESPONDING positions. (Shown above with angles 4 and 5 and again with angles 3 and 6.)

alternate interior angles

Two angles that lie BETWEEN the two lines and on OPPOSITE SIDES of the transversal. (Shown above with angles 4 and 5 and again with angles 3 and 6.)

consecutive interior angles

Two angles that lie BETWEEN the two lines and on the SAME SIDE of the transversal. (Shown above as angles 4 and 6 and again with angles 3 and 5)

alternate exterior angles

Two angles that lie OUTSIDE of the two lines and on OPPOSITE SIDES of the transversal. (Shown above as angles 2 and 7 and again with angles 1 and 8.)