6.3 PARALLEL LINES AND A TRANSVERSAL:
If a transversal intersects two parallel lines then each pair of corresponding angles are equal.
Interior angles on the same side of the transversal are also called as consecutive interior
angles or co – interior angles
If a transversal intersects two lines such that a pair of corresponding angles are equal then
the two lines are parallel to each other
If a transversal intersects two parallel lines then each pair of alternate interior angles are equal.
A line which intersects two or more lines at distinct points is called a transversal
Angles formed by a transversal :
( i ) Corresponding Angles
( a ) ∠ 1 and ∠ 5 ( b ) ∠ 2 and ∠ 6
( c ) ∠ 3 and ∠ 7 ( d ) ∠ 4 and ∠ 8
( ii ) Alternate interior angles
( a ) ∠ 4 and ∠ 6 ( b ) ∠ 3 and ∠ 5
( iii ) Alternate exterior angles
( a ) ∠ 1 and ∠ 7 ( b ) ∠ 2 and ∠ 8
( iv ) Interior Angles on same side of transversal
( a ) ∠ 4 and ∠ 5 ( b ) ∠ 3 and ∠ 6