The radius of the large circle is 3 decimeters, the radius of the small circle is 2 decimeters, and the area of the small circle is equal to the area of the large circle.
大圆半径是3分米，小圆半径是2分米，小圆面积是大圆面积的多少．
<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<result>4/9 = around 0.444444</result>