At what angle must 3 forces, of which $a=2488 \mathrm{~kg}, b=927 \mathrm{~kg}, c=1815 \mathrm{~kg}$, act so that the point of attack remains in equilibrium?
$\alpha=52^{\circ} 45^{\prime} 20^{\prime \prime}, \quad \beta=162^{\circ} 44^{\prime} 48^{\prime \prime}, \quad \gamma=144^{\circ} 29^{\prime} 52^{\prime \prime}$.