<u>Answer-</u>
1 and 2 are congruent because they are a pair of corresponding angles
<u>Solution-</u>
When two lines are crossed by another line (called the transversal), the angles in matching corners are called Corresponding Angles.
<em>The parallel case</em>
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If the transversal cuts across parallel lines, then corresponding angles have the same measure.
<em>The non-parallel case
-</em>
If the transversal cuts across lines that are not parallel, the corresponding angles have no particular relationship to each other.
In the given diagram, 1 and 2 are a pair of corresponding angles. And as the two lines are parallel, so 1 and 2 are congruent.