posted by hello .
given: segment AB is paralell to segment DC; segment AB is congruent to segment to DC
prove: triangle ABC is congruent to triangle CDA
1. segment AB is congruent to segment DC
2.segment AC is congruent to segment AC
3.segment AB is paralell to segment DC
4.angle BAC is congruent to angle DCA
5.triangle ABC is congruent to triangle CDA
(i need to find the reasons)???
It is hard to provide geometry assistance without a figure to work with. Your problem seems to be representable by a parallelogram ABCD, where AC is a diagonal. The angle BAC is the same as the angle ACD, because they are formed by a line intersecting parallel lines AB and CD. (There is a theroem about that). That means triangles ABC and ACD have two pairs of sides (AB/CD and the common side AC)with an included angle congruent. That makes the triangles congruent. (Side-Angle-Side theorem).