You want to erect a pole of a height 10 mt with the support of three ropes. If each rope has to make an angle 30° with the pole, then the length of the rope is

Height of the pole $=10m$

Let the length of each rope $=x$

Angle made by the rope with the pole 30°

From the figure,

$\cos 30°=\frac{10}{x}$

$\frac{\sqrt{3}}{2}=\frac{10}{x}$

$x=\frac{20}{\sqrt{3}}=\frac{20}{1.732}=11.55m$

length of each rope $=11.55m$