A cylinder, the diameter of the upper base is 12cm, what is the area of the lower base in cm**2.
一个圆柱，上底面直径是12cm，下底面的面积是多少cm**2．
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">3.14 * 36</gadget>
<output>113.04</output>

<result>113.04</result>