Page 3 - ln1

2) All the pairs of ∠3 = ∠6
alternate interior
angles are equal. ∠4 = ∠5

3) The two Interior angles
which are on the same ∠3 + ∠5 = 180°
side of the transversal
will always be ∠4 + ∠6 = 180°
supplementary
( their sum = 180° )
Checking for 1) If a transversal passes through
Parallel Lines  This is the two lines so that the pairs of
inverse of the corresponding angles are equal,
above properties then these two lines must be
of the parallel.
transversal of
parallel lines 2) If a transversal passes through
two lines so that the pairs of
alternate interior angles are
equal, then these two lines must
be parallel.

3) If a transversal passes through
two lines so that the pairs of
interior angles on the same side
of the transversal are
supplementary, then these two
lines must be parallel.