Question

ABCD is a trapezium in which AB | | CD and AD =BC (see the given figure). Show that $\Delta ABC\cong \Delta BAD$.

Answer 1

In $\Delta ABC$ and $\Delta ABD$,
AB=BA (Common side)
BC=AD (Given)
$\angle B=\angle A$ (Proved before)
$\Delta ABC\cong \Delta ABD$ (SAS congruence rule).