Step-by-step explanation:
First you have to add up all of the numbers that make up the perimeter of this arrow.
3+3+1+.5+.5+1.8+1.8=11.6
You than want to divide this number by 2 to find the half perimeter you have to work with, which is 5.8.
A simple shape you can make is a square, with each side being 1.45 m.