The diameter of a circular flower bed is 6m. Now pave a gravel road with a width of 1m along the periphery of the flower bed. If the cost of the gravel road is 80 yuan per square meter, how much is the total cost of building this gravel road?
一个圆形花坛的直径是6m，现在沿花坛的外围铺一条宽1m的石子路，若每平方米石子路面造价80元，建造这条石子路共需多少元？
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

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

<gadget id="calculator">16 - 9</gadget>
<output>7</output>

<gadget id="calculator">3.14 * 7 * 80</gadget>
<output>1_758.4</output>

<result>1_758.4</result>