Uncle Wang led the sheep to graze. He tied the sheep to a stake with a 2.5-meter-long rope. The rope used to tie the wooden stake was 0.9 meters. What is the maximum area that the sheep grazes?
王大伯牵着羊去吃草，他用2.5米长的绳子把羊拴在了一段本桩上，栓木桩的绳子用去了0.9米，这只羊吃草的面积最多是多少平方米？
<gadget id="calculator">2.5 - 0.9</gadget>
<output>1.6</output>

<gadget id="calculator">1.6 ** 2</gadget>
<output>2.56</output>

<gadget id="calculator">3.14 * 2.56</gadget>
<output>8.0384</output>

<result>8.0384</result>