An infinite slope with slope angle $\beta=22^{\circ}$ consists of soil with the following properties:
Unit weight $\gamma=15.72 ~\mathrm{kN} / \mathrm{m}^{3}$
Cohesion $c^{\prime}=12 ~\mathrm{kPa}$
Angle of internal friction $\phi^{\prime}=15^{\circ}$
The critical height of the slope (in $\text{m}$) is $\_\_\_\_$ (rounded off to two decimal places).
