Use a rectangular board with a length of 5m and a width of 3m to make the largest circular tabletop. What is the area of the removed part?
用一块长为5m宽为3m的长方形木板做一个最大的圆形桌面，去掉部分的面积是多少．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) ** 2</gadget>
<output>9/4 = around 2.25</output>

<gadget id="calculator">3.14 * (9/4)</gadget>
<output>7.065</output>

<gadget id="calculator">15 - 7.065</gadget>
<output>7.935</output>

<result>7.935</result>