Answer :
w - width
l - length
p - perimeter
The perimeter is 72 cm (p=72).
The length is twice the width (l=2w).
The formula for perimeter is 2w+2l=P.
[tex]p=72 \\ l=2w \\ \\ 2w+2l=p \\ 2w+2 \cdot 2w=72 \\ 2w+4w=72 \\ 6w=72 \\ w=12 \\ \\ l=2w=2 \cdot 12 =24[/tex]
Check the answer:
[tex]2 \cdot 12 + 2 \cdot 24 \stackrel{?}{=} 72 \\ 24+48 \stackrel{?}{=} 72 \\ 72 \stackrel{?}{=} 72 \\ \hbox{true}[/tex]
The length of the photo is 24 cm, the width of the photo is 12 cm.
l - length
p - perimeter
The perimeter is 72 cm (p=72).
The length is twice the width (l=2w).
The formula for perimeter is 2w+2l=P.
[tex]p=72 \\ l=2w \\ \\ 2w+2l=p \\ 2w+2 \cdot 2w=72 \\ 2w+4w=72 \\ 6w=72 \\ w=12 \\ \\ l=2w=2 \cdot 12 =24[/tex]
Check the answer:
[tex]2 \cdot 12 + 2 \cdot 24 \stackrel{?}{=} 72 \\ 24+48 \stackrel{?}{=} 72 \\ 72 \stackrel{?}{=} 72 \\ \hbox{true}[/tex]
The length of the photo is 24 cm, the width of the photo is 12 cm.