Answer:
11 units
Step-by-step explanation:
Length of side PS can be calculated using the distance formula, 
Where,
(the coordinate of P is gotten from the graph)
(given)



(x,y)
sub given points and see if true
A, (0,-13)
x=0
y=-13
3(-13)=5(0)-13
-39=0-13
-39=-13
false (other user was just guessing)
B. (3,1)
x=3,
y=1
3(1)=5(3)-13
3=15-13
3=2
false
C. (7,7)
x=7
y=7
3(7)=5(7)-13
21=35-13
21=22
false
D. (-6,-1)
3(-1)=5(-6)-13
-3=-30-13
-3=-43
false
answer is none of them
Let
x---------> the length side of rectangle
y---------> the width side of rectangle
we know that
x=2y-----> equation 1
area=x*y-------> 28800=x*y------> equation 2
substitute 1 in 2
28800=[2y]*y-----> 28800=2y²-------> y²=14400------> y=120 m
x=2*y----> x=2*120------> x=240 m
the answer is
the length side of rectangle is 240 m
the width side of rectangle is 120 m