Mount Fuji in Japan is a circular volcano with a base diameter of 60 kilometers. How many square kilometers does it cover?
日本富士山是个圆形火山，底座直径60千米，它的占地面积是多少平方千米？
<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<gadget id="calculator">30 ** 2</gadget>
<output>900</output>

<gadget id="calculator">3.14 * 900</gadget>
<output>2_826</output>

<result>2_826</result>