Answer:
t and u are parallel lines
s and t are also parallel lines
Step-by-step explanation:
If two parallel lines are cut by a transversal ,
then in it
pair of alternate angle are equals, similarly vice versa
if pair of alternate angle are equals then lines are parallel
pair of corresponding angles are equal and vice-versa
for example
in the given problem
if line t and u are parallel (note we have assumed this to give example of parallel lines)
then angle 7 and 9 are called alternate angles
pair of angles 5 and 9 are corresponding angles.
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given
∠8 = ∠10 which are alternate angles for line t and u and s is transversal for it,
thus t and u are parallel lines
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∠1 = ∠3 as they vertically opposite angles
and we know that pair of vertically opposite angles are equal
given
∠1 = ∠7
thus
∠3 = ∠7
as pair of angles ∠3 and ∠7 are corresponding angles. and are equal and hence line s and t are also parallel.
