Explanation:
in the figure AB & CD are equal and AD & BC are parallel
therefore, the angle BAD and angle CDA are equal
In, ΔBAD & ΔCDA
line BA = line CD
angle BAD = angle CDA
line AD is common in bith triangles
so, ΔBAD is congrent to ΔCDA.
therefore, line BD = line AC as ΔBAD is congrent to ΔCDA.
Hence, proved