"If two sides and an angle of one triangle are equal to two sides and an angle of another triangle,then the two triangles must be congruent." Is the statement true? Why?

If in $\Delta ABC, AC > AB > BC$,then find the greatest angle of the triangle.

State whether each of the following statements is true or false:
$(1)$ In $\Delta ABC$ and $\Delta PQR$,$AB = PQ$,$BC = PR$ and $\angle B = \angle P$,then $\Delta ABC \cong \Delta PQR$.
$(2)$ The exterior angles at two vertices of any triangle cannot both be acute.

$PL, QM$ and $RN$ are the altitudes of $\Delta PQR$. If $PL = QM = RN$,then by $RHS$ criterion of congruence,prove that $\Delta PQR$ is an equilateral triangle.

Prove that the sum of any two sides of a triangle is greater than twice the median with respect to the third side.

$P$ is a point on the bisector of $\angle ABC$. If the line through $P$,parallel to $BA$,meets $BC$ at $Q$,prove that $\triangle BPQ$ is an isosceles triangle.