Answer:
Opposite interior angles of a parallelogram are congruent.
Step-by-step explanation:
To answer this question let's do it step by step. So step
1) Consider the parallelogram GDEF
2) Trace a straight line, since two points define a line. Trace and another
3) Consider these pair of parallel segments:
4) Now let's examine the angles. According to Euclides since DE and GF are parallels we can say that:
5) This step is the conclusion of the previous one, since alternate interior angles have the same measure, so
Opposite interior angles of a parallelogram are congruent.