The radius of the large circle is twice the radius of the small circle. The area of the large circle is 18.84 square meters. How many square meters is the area of the small circle?
大圆半径是小圆半径的2倍，大圆的面积是18.84平方米，小圆的面积是多少平方米？
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">18.84 / 4</gadget>
<output>4.71</output>

<result>4.71</result>