Help please will mark brainliest!!

Answer:
5,4 km
Step-by-step explanation:
we know the area and the width.
the formula of the area of a parallelogram is
A = length x width
if we substitute the values that we know, we have
23,1 = x * 4,3
to find x we have to divide the two members by 4,3
x = 23,3/4,3 = 5,4 km