REmember that te perimeter is the sum of all its length sides
see the attached figure to better understand the problem
we have a symetrical figure
i will calculate the perimeter of ABCDE and then multiply by 4 to obtain the total perimeter
so
AB=2
BC------> applying Pythagorean Theorem
BC^2=2^2+2^2
BC^2=8
BC=2.83
CD=2
DE ------> applying Pythagorean Theorem
DE^2=2^2+2^2
DE^2=8
DE=2.83
AB+BC+CD+DE=2+2.83+2+2.83=9.66
multiply by 4
4*9.66=38.64 units
Round the answer
P=39 units