Parallel Lines

Parallel Lines

1. If two lines in a two dimensional plane do not intersect each other, they are called parallel lines.

   • Line AB & CD are parallel lines.
   • Any line which intersects the parallel lines is called transversal line.
     • Corresponding angles are angles which are formed in corresponding corners with the transversal when two parallel lines are intersected by any other line i.e. transversal.
       • Alternate interior angles are the pair of angles on the inner side of the two parallel lines but on the opposite side of the transversal.
         • Alternate interior angles are angle 1 & 2 and angle 3 & 4.
         • Alternate exterior angles are the pair of angles on the outer side of the two parallel lines but on the opposite side of the transversal.
           • Alternate exterior angles are angle 1 & 2 and angle 3 & 4.
           • Co-interior angles are the two angles that are on the same side of the transversal. Co-interior angles are the interior angles and its sum up to 180 degrees.
             • Angle 1 & 2 and angle 3 & 4 are co-interior angles.
             • The distance between parallel lines does not change, it is the same every where.
               • Lines, parallel to a given line in a plane, are parallel to each other.
                 • Line a & b and line b & c are parallel. So, line a & c are parallel.
                 • Two lines in the same plane perpendicular to a given line are parallel to each other.
                   • Division of a line segment into 'n' equal parts, can be done by constructing parallel lines. e.g. line segment AB=5cm and it is divided internally into 6 equal parts.
                     • A line segment can be divided internally in a given ratio by constructing parallel lines. e.g. line segment AB=5.5 cm and it is divided internally in the ratio 2:3.

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