For the correspondence $ABC \leftrightarrow PRQ$ between $\Delta ABC$ and $\Delta PQR,$ the side $\ldots$ corresponds to $AB.$

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

If $\Delta XYZ$ has $XY = 7 \, cm$ and $YZ = 10 \, cm$,the perimeter of $\Delta XYZ$ is greater than how many centimeters?

In $\Delta ABC$ and $\Delta PQR$,if $\frac{AB}{PQ} = \frac{BC}{RQ} = \frac{AC}{PR} = 1$,then $\Delta ABC \cong \Delta \ldots \ldots \ldots$

Write the measures of its sides in ascending order in each of the following triangles:
$(1)$ In $\Delta ABC$,$\angle B = 70^{\circ}$ and $\angle C = 20^{\circ}$.

Show that in a quadrilateral $ABCD$,$AB + BC + CD + DA > AC + BD$.