9514 1404 393
Answer:
4 cm
Explanation:
The sum of length and width is half the perimeter, so is 12 cm.
The width : length ratio is 1 : 2. The width is 1/(1+2) = 1/3 of the total of length and width, so is ...
(1/3)(12 cm) = 4 cm
The width of the rectangle is 4 cm.