**How Do You Know If Two Line Segments Are Parallel**. If the two lines are parallel then their slopes are equal. To find a segment parallel to another segment and through a given point using paper folding techniques requires two steps, the first step is to find a line perpendicular to the.

Y = m1x + b1. If any pair of corresponding angles, alternate interior angles, alternate exterior angles are equal or consecutive interior angles are supplementary, then two line segments are parallel. M1 = m2 ( the two lines have the same slope) b1 != b2 (the.