The radius of a small circle is 3cm, and that of a large circle is 5cm. The simplest integer ratio of the area of a large circle to that of a small circle is______ .

The radius of a small circle is 3cm, and that of a large circle is 5cm. The simplest integer ratio of the area of a large circle to that of a small circle is______ .

The area of the small circle is: π × 32 = 9 π, the area of the big circle is: π × 52 = 25 π, the ratio of the area of the small circle to the area of the big circle is: 9 π: 25 π = 9:25, so the answer is: 9:25