Correct Answer - Option 2 : 5 : 4

**Calculation:**

Let a be the smaller side of rectangle,

4a is the length longer side.

Area of rectangle = Area of square

⇒ a × 4a = c^{2}

⇒ c = 2a

Perimeter of rectangle = a + 4a + 4a + a =10a

Perimeter of square = 4 × 2a = 8a

Ratio is 10a : 8a = 5 : 4

**∴ The ratio of their perimeter of rectangle to square is 5 : 4.**