The difference of any two sides of a triangle is $\ldots \ldots \ldots$ than the third side.

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

If $\Delta ABC \cong \Delta DEF$,and the area of $\Delta ABC$ is $58 \ cm^2$,then find the area of $\Delta DEF$ in $cm^2$.

In $\Delta ABC$,$AB = AC$ and $\angle B = 75^{\circ}$,then $\angle C = \dots$ (in $^{\circ}$)

In $\triangle PQR$,$\angle P = 70^{\circ}$ and $\angle R = 30^{\circ}$. Which side of this triangle is the longest? Give a reason for your answer.

In $\Delta XYZ$,$XY > XZ$ and $P$ is any point on the side $YZ$. Prove that $XY > XP$.