In the above diagram the minimum possible distance between Point P and L will be calculated using the Pythagoras theorem as follows:
[latex]{(PL)}^{2} = {(PZ)}^{2} + {(ZL)}^{2}[/latex]
Here the distance between point P and Z is 25m and the distance between point Z and L is 30 meters so
[latex]{(PL)}^{2} = {(25)}^{2} + {(30)}^{2}[/latex]
[latex]{(PL)}^{2} = (625) + (900)[/latex]
[latex]{(PL)}^{2} = (1525)[/latex]
(PL)= 39m approx.
So the minimum possible distance between point P and L is approximately 39m.