Solution:
We have re-drawn the given diagram, as we can see the given rectangle is actually divided into two parts.
one is Large square and the other one is a smaller rectangle.
Now we will apply the Pythagoras theorem in the larger triangle which is inside the square.
So we can write
[tex]Diagonal_1=\sqrt{15^2+15^2}= 21.213[/tex]
Now we will apply the Pythagoras theorem in the smaller triangle which is inside the smaller rectangle.
So we can write
[tex]Diagonal_2=\sqrt{15^2+8^2}= 17[/tex]
The approximate sum of the lengths of the two sidewalks, shown as dotted lines[tex]=21.2+17=38.2[/tex] m
Hence the correct option is D
