A short shoe external drum brake is shown in the figure. The diameter of the brake drum is $500 \: mm$. The dimensions $a=1000 \: mm, \: b=500 \: mm$ and $c=200 \: mm$. The coefficient of friction between the drum and the shoe is $0.35$. The force applied on the level $F=100 N$ as shown in the figure. The drum is rotating anti-clockwise. The braking torque on the drum is ______ $N \cdot m$ (round off to two decimal places).