Questions in trigonometry

Select	Question
	In $\Delta ABC$ , $(b-c)\cot \frac{A}{2}+(c-a)\cot \frac{B}{2}+(a-b)$ $\cot \frac{C}{2}$ is equal to
	In a triangle $ABC$ if $2{{a}^{2}}{{b}^{2}}+2{{b}^{2}}{{c}^{2}}=$ ${{a}^{4}}+{{b}^{4}}+{{c}^{4}}$ , then angle B is equal to
	Area of the triangle is $10\sqrt{3}$ sq. cm, angle $C={{60}^{o}}$ and its perimeter is 20 cm, then side c will be
	In triangle$ABC$ if $A+C=2B$ , then $\frac{a+c}{\sqrt{{{a}^{2}}-ac+{{c}^{2}}}}$ is equal to
	The two adjacent sides of a cyclic quadrilateral are 2 and 5 and the angle between them is ${{60}^{o}}$. If the third side is 3, the remaining fourth side is
	In a triangle $ABC,$ $a=4,b=3$ , $\angle A={{60}^{o}}$. Then c is the root of the equation
	If $a=2,b=3,c=5$ in $\Delta ABC$ , then $C =$
	If $A={{30}^{o}},a=7,b=8$ in $\Delta ABC$ , then B has
	If $b=3,c=4$ and $B=\frac{\pi }{3}$ , then the number of triangle that can be constructed is
	If ${{a}^{2}},{{b}^{2}},{{c}^{2}}$ are in A. P. then which of the following are also in A.P.