What is the area of a circle with a radius of 6 cm and a diameter of 12 cm?
半径是6厘米，直径是12厘米的圆的面积是多少？
<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

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

<result>113.04</result>