A cow is tied to a vertex of a rectangular concrete platform with a length of 5 meters and a width of 2 meters. The rope is 4 meters long. What is the range of movement of the cow? (The result keeps π)
一只牛被栓在长为5米，宽2米的长方形水泥台的一个顶点上，绳子长4米，问牛的活动范围是多大？(结果保留π)
<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">270 / 360</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">3.14 * 16 * (3/4)</gadget>
<output>37.68</output>

<gadget id="calculator">4 - 2</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

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

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

<gadget id="calculator">37.68 + 3.14</gadget>
<output>40.82</output>

<result>40.82</result>