When two lines are intersected by a third line, if one pair of alternate interior angles formed is congruent, then the two lines are parallel to each other. Two pairs of such alternate interior angles are formed.
Continue ReadingOne of the most important theorems in geometry has to do with alternate interior angles; this theorem on alternate interior angles is used extensively in geometry. It is used to prove two lines parallel in problems that require proof. When two lines are intersected by a third line, eight angles are formed at the two distinct points of intersection. The alternate interior angles are formed on either side of this third line.
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