EXPLANATION :
From the problem, we have an elevator that is 0.9m by 0.9m
If we draw a diagonal line, the length of a diagonal line of a square is :
[tex]d=s\sqrt{2}[/tex]
where s is the side of the square.
That will be :
[tex]\begin{gathered} d=0.9\sqrt{2} \\ d=1.27\text{ m} \end{gathered}[/tex]
So you can apply the social distancing by standing at the opposite corners of the elevator.
