A square grass field with a side length of 3 meters. A tree is planted at the vertices of two opposite corners. A sheep is tied to each tree. The length of the rope is 3 meters. How many grasses can two sheep eat in total? How big is the area? (Pi is taken as 3.14)
一个正方形的草地，边长是3米，在两个对角的顶点处各种一棵树，树上各拴一只羊，绳长都是3米，问两只羊共能吃到草的面积有多大？(圆周率取3.14)
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">(1/4) * 3.14 * 9</gadget>
<output>7.065</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 3 * 3</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">7.065 - (9/2)</gadget>
<output>2.565</output>

<gadget id="calculator">2.565 * 2</gadget>
<output>5.13</output>

<result>5.13</result>