The correct answer is 39 units.
Parameter is the sum of the lengths of all sides of a polygon. The sides of the polygon are PT, TS, SR, RQ, and QP. To get the length of a side, we use the distance formula:
d =

Each vertex in the polygon has its corresponding points:
P (-2,11)
T (8, 7)
S (1, 7)
R (2, 0)
Q (-4,5)
So to get the length of side PT, we use the distance formula and the vertices of side PT:
P

= (-2, 11)
T

= (8, 7)
The length of PT is

The same procedure is done for the other 4 sides and the following are the answers:
TS =

SR =

RQ =

QP =

And by adding all the sides, you get the perimeter:

By rounding off, the answer is 39 units.