If the value of $1$ radian in degree is $\frac{k}{\pi }$ degree then find the value of $k$.

In a regular decagon, if the value of each interior angle in the circular measure is $\frac{\mathrm{k\pi }}{5}$ radian then find the value of $k$.

Find the value:

$\frac{1}{2}\cos e{c}^2\left(\frac{\pi }{3}\right)+se{c}^2\left(\frac{\pi }{4}\right)-2co{t}^2\left(\frac{\pi }{3}\right)$

Find the value:

$\cos \left(45°\right)\tan \left(60°\right)\mathrm{cosec}\left(45°\right)\sec \left(30°\right)$

If $x^2={\sin }^2\left(30°\right)+co{t}^2\left(45°\right)-{\cos }^2\left(60°\right)$, then what is the value of $x$?