$\displaystyle P=2l+ 2w$

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown. 

$\displaystyle 52=2l+2(13)$

$\displaystyle 52=2l+26$

Subtract $\displaystyle 26$ from both sides

$\displaystyle 52-26=2l+26-26$

$\displaystyle 26=2l$

Divide $\displaystyle 2$ by both sides

$\displaystyle \frac{26}{2}=\frac{2l}{2}$

$\displaystyle 13=l$

$\displaystyle P=2l+ 2w$

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown. 

$\displaystyle 38=2l+2(6)$

$\displaystyle 38=2l+12$

Subtract $\displaystyle 12$ from both sides

$\displaystyle 38-12=2l+12-12$

$\displaystyle 26=2l$

Divide $\displaystyle 2$ by both sides

$\displaystyle \frac{26}{2}=\frac{2l}{2}$

$\displaystyle 13=l$

$\displaystyle P=2l+ 2w$

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown. 

$\displaystyle 36=2l+2(10)$

$\displaystyle 36=2l+20$

Subtract $\displaystyle 20$ from both sides

$\displaystyle 36-20=2l+20-20$

$\displaystyle 16=2l$

Divide $\displaystyle 2$ by both sides

$\displaystyle \frac{16}{2}=\frac{2l}{2}$

$\displaystyle 8=l$

$\displaystyle P=2l+ 2w$

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown. 

$\displaystyle 52=2l+2(11)$

$\displaystyle 52=2l+22$

Subtract $\displaystyle 22$ from both sides

$\displaystyle 52-22=2l+22-22$

$\displaystyle 30=2l$

Divide $\displaystyle 2$ by both sides

$\displaystyle \frac{30}{2}=\frac{2l}{2}$

$\displaystyle 15=l$

$\displaystyle P=2l+ 2w$

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown. 

$\displaystyle 58=2l+2(19)$

$\displaystyle 58=2l+38$

Subtract $\displaystyle 38$ from both sides

$\displaystyle 58-38=2l+38-38$

$\displaystyle 20=2l$

Divide $\displaystyle 2$ by both sides

$\displaystyle \frac{20}{2}=\frac{2l}{2}$

$\displaystyle 10=l$

$\displaystyle P=2l+ 2w$

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown. 

$\displaystyle 54=2l+2(17)$

$\displaystyle 54=2l+34$

Subtract $\displaystyle 34$ from both sides

$\displaystyle 54-34=2l+34-34$

$\displaystyle 20=2l$

Divide $\displaystyle 2$ by both sides

$\displaystyle \frac{20}{2}=\frac{2l}{2}$

$\displaystyle 10=l$

$\displaystyle P=2l+ 2w$

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown. 

$\displaystyle 70=2l+2(15)$

$\displaystyle 70=2l+30$

Subtract $\displaystyle 30$ from both sides

$\displaystyle 70-30=2l+30-30$

$\displaystyle 40=2l$

Divide $\displaystyle 2$ by both sides

$\displaystyle \frac{40}{2}=\frac{2l}{2}$

$\displaystyle 20=l$

$\displaystyle P=2l+ 2w$

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown. 

$\displaystyle 72=2l+2(15)$

$\displaystyle 72=2l+30$

Subtract $\displaystyle 30$ from both sides

$\displaystyle 72-30=2l+30-30$

$\displaystyle 42=2l$

Divide $\displaystyle 2$ by both sides

$\displaystyle \frac{42}{2}=\frac{2l}{2}$

$\displaystyle 21=l$

$\displaystyle P=2l+ 2w$

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown. 

$\displaystyle 12=2l+2(3)$

$\displaystyle 12=2l+6$

Subtract $\displaystyle 6$ from both sides

$\displaystyle 12-6=2l+6-6$

$\displaystyle 6=2l$

Divide $\displaystyle 2$ by both sides

$\displaystyle \frac{6}{2}=\frac{2l}{2}$

$\displaystyle 3=l$

$\displaystyle P=2l+ 2w$

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown. 

$\displaystyle 24=2l+2(3)$

$\displaystyle 24=2l+6$

Subtract $\displaystyle 6$ from both sides

$\displaystyle 24-6=2l+6-6$

$\displaystyle 18=2l$

Divide $\displaystyle 2$ by both sides

$\displaystyle \frac{18}{2}=\frac{2l}{2}$

$\displaystyle 9=l$