17.
From the figure we can conclude:
[tex]\begin{gathered} length=l=4-(-3)=7 \\ width=w=2-(-1)=3 \end{gathered}[/tex]
In order to calculate how much string will he need, we need to calculate the perimeter. The perimeter can be calculated as follows:
[tex]\begin{gathered} P=2w+2l \\ so: \\ P=2(7)+2(3)=14+6=20 \end{gathered}[/tex]
Answer:
He will need 20 units
