Question

prove that opposite angle of a parallel gram are equal

Answer 1

In angle ABC and CDA,we have:
AB =CD ( given )
BC = AD (given )
AC = CA ( common )
angle ABC congruence angle CAD
angle BAC = angle DCA
But , these are alternate interior angles.
AB parallel DC.
Similarly, AD parallel BC .
Hence, ABCD is a parallelogram.....
Hope ....you understand. .....