Given the order of the vertices of the trapezoid (ABCD) and the coordinates, we can calculate the length of each side and add them up to get the perimeter.
We know A(-3,5) B(3,5) C(5,-3) and D(-5,-3),
then
mAB=(3-(-3))=6 (since the other coordinate= 5 is the same for A & B.
mBC=sqrt((5-3)^2+(-3-5)^2)=sqrt(4+64)=sqrt(68)
mCD=(5-(-5))=10 (since the other coordinate=-3 is the same for C & D.
m(DA)=sqrt((-5-(-3))^2+(-3-(-5))^2)=sqrt(68)
Therefore perimeter
=6+sqrt(68)+10+sqrt(68)
=16+2sqrt(2^2 * 17)
=16+4sqrt(17) [exact]
=32.5 [approx.]