The ratio of the circumferences of two circles is 2:3, and the difference in area is 30 square centimeters, what is the area of the larger circle?
两个圆周长比是2：3，面积相差30平方厘米，较大圆的面积是多少．
<gadget id="calculator">9 - 4</gadget>
<output>5</output>

<gadget id="calculator">30 / 5</gadget>
<output>6</output>

<gadget id="calculator">6 * 9</gadget>
<output>54</output>

<result>54</result>