The school has a circular lotus pond with a diameter of 30 meters. How many square meters does it cover?
学校有一个圆形荷花池，直径是30米，它占地面积是多少平方米？
<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">15 ** 2</gadget>
<output>225</output>

<gadget id="calculator">3.14 * 225</gadget>
<output>706.5</output>

<result>706.5</result>