The radius of the large circle is twice the radius of the small circle. The area of the large circle is 12 square meters larger than the area of the small circle. What is the area of the small circle in square meters?
大圆半径是小圆半径的2倍，大圆面积比小圆面积多12平方米，小圆面积是多少平方米．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">4 * 1</gadget>
<output>4</output>

<result>4</result>