The diameter of a circular pool is 8 meters, and a path with a width of 1 meter is built around it. What is the area of the path in square meters?
一个圆形水池的直径是8米，在它的周围修一条宽1米的小路，小路的面积是多少平方米？
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

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

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<gadget id="calculator">78.5 - 50.24</gadget>
<output>28.26</output>

<result>28.26</result>