In $\Delta PQR$,$PQ = 7.5 \, cm$,$QR = 6.2 \, cm$ and $a < PR < b$,then find the values of $a$ and $b$ in $cm$.

The sum of the three angles of a triangle is $\ldots \ldots \ldots$ (in $^o$)

In $\Delta ABC$,$\angle A + \angle B = 80^{\circ}$ and $\angle B + \angle C = 150^{\circ}$. Find the measure of each angle of $\Delta ABC$.

In $\Delta PQR$,$\angle Q = \angle R$ and $PQ = 6.5 \, cm$,then find $PR$. (in $, cm$)

In $\Delta ABC$,$AB > BC > CA$. Write the measure of the angles of the triangle in ascending order.

Write True or False and justify your answer:
$ABC$ and $BDE$ are two equilateral triangles such that $D$ is the mid-point of $BC.$ Then $\operatorname{ar}(\triangle BDE) = \frac{1}{4} \operatorname{ar}(\triangle ABC).$