$$ \begin{cases} mg&=413\ut{N}\\\end{cases} $$$$ \begin{cases} \Sigma F_x&=0\\\Sigma F_y&=0\\\Sigma \tau&=0\\\end{cases} $$$$ \begin{cases} 0&=N_x-T\sin\theta\\0&=N_y+T\cos\theta-mg\\0&=mgL\sin\br{2\theta}-TL\sin\theta\\\end{cases} $$$$\ab{a}$$$$ \begin{aligned}T&=2 mg \cos\theta\\&=413\sqrt3\ut{N}\\&\approx 715.3369835259463\ut{N}\\&\approx 715\ut{N}\\\end{aligned} $$$$\ab{b}$$$$ \begin{aligned..