If the lengths of the sides of a triangle are $3, 5, 7$,then the largest angle of the triangle is

If in a $\Delta ABC$,$b = 2$,$c = \sqrt{3}$,$\angle A = \frac{\pi}{6}$,then $R = $?

If the sides of a triangle are $6, 10$ and $14$,then the triangle is

In a triangle $ABC,$ if $a \sin A = b \sin B,$ then the nature of the triangle is:

In $\triangle ABC$ with the usual notations,if $\left(\tan \frac{A}{2}\right)\left(\tan \frac{B}{2}\right)=\frac{3}{4}$,then $a+b=\ldots$ (in $c$)

In $\Delta ABC$,$8 \Delta = (b + c)(bc + 1)$,then the circumradius of $\Delta ABC$ is (where $\Delta$ denotes the area of the triangle and $b, c$ are the lengths of sides $AC$ and $AB$ respectively):