The circumference of a circle is 62.8 decimeters, if its diameter is reduced by 4 decimeters, the area of the circle will be reduced by how many square decimeters.
一个圆的周长是62.8分米，如果它的直径减少4分米，圆的面积就减少多少平方分米．
<gadget id="calculator">62.8 / 3.14</gadget>
<output>20</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">20 - 4</gadget>
<output>16</output>

<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

<gadget id="calculator">3.14 * 64</gadget>
<output>200.96</output>

<gadget id="calculator">314 - 200.96</gadget>
<output>113.04</output>

<result>113.04</result>