The areas of two squares are 16:9 . The ratio of their perimeter is

4:3

ratio of the area : a^2:b^2 (16:9 => 4^2:3^2) Which confirms the ratio of their sides are 4:3. Substituting it in the perimeter. ratio of the perimeter = 4a : 4b => 4x4 : 4x3 (4 gets cancelled) => 4:3 Hence the anwer is 4:3