Respuesta :
Answer:
1. Vertical Angles Theorem
2. Converse of Alternate Interior Angles Theorem
Step-by-step explanation:
First option:
Lines AC and BD intersect at point E. Angles AEB and CED are opposite angles formed when these two lines intersect and are called vertical angles. By vertical angles theorem, these angles are congruent. So,
Vertical Angles Theorem
Second option:
[tex]\triangle BEC\cong \triangle DEA[/tex] by SAS postulate, then
[tex]\angle CBE\cong \angle ADE[/tex] as corresponding sides of congruent triangles.
Converse of Alternate Interior Angles Theorem states that if two lines are cut by a transversal and the alternate interior angles are congruent, then the lines are parallel.
So, [tex]\overline{BC}\cong \overline{AD}[/tex] by
Converse of Alternate Interior Angles Theorem