Answer:
The sequence is used to prove AD = BC is
First prove ABC is congruent to CDA, and then state AD and BC are corresponding sides of the triangles.
Explanation:
let us assume that ABCD is a parallelogram.
thus AB is parallel to CD
AC is become transversal.
Take ΔADC and ΔABC.
∠DAC =∠ BCA
( by property of alternate angle )
AC = AC
( common side of both triangle.)
∠ACD= ∠BAC
( by property of alternate angle )
Thus by using ASA congruence property.
ΔADC ≅Δ ABC
Thus
AD = BC
( By corresponding part of the congruent triangle property )
Hope this helped!