The Solution:
Given:
Let the width be W.
Length: L= 3W
P=perimeter=49
Required:
Find the length.
The Formula:
[tex]P=2(L+W)[/tex]Substitute:
[tex]49=2(3W+W)[/tex][tex]\begin{gathered} 49=2(4W) \\ \\ 49=8W \end{gathered}[/tex][tex]W=\frac{49}{8}=6.125\text{ units}[/tex]The length is:
[tex]L=3(6.125)=18.375\text{ units}[/tex]Answer:
18.375 units.