There is a rectangular wooden board with a length of 18 decimeters and a width of 10 decimeters. It is necessary to use it to make a round table as large as possible. What is the area of the round table in square meters?
有一块长18分米，宽10分米的长方形木板，要用它做一个尽可能大的圆桌面，这个圆桌面的面积是多少平方米？
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3.14 * (1/4)</gadget>
<output>0.785</output>

<result>0.785</result>