circular pool is surrounded by a cobblestone path with a width of 1 meter. It is known that walking along the outer circle of the path is 31.4 meters. Find the area of the pool.
一个圆形水池外面环绕一条1米宽的鹅卵石小路，已知沿小路外圈走一圈是31.4米，求水池的面积．
<gadget id="calculator">31.4 / 3.14 / 2</gadget>
<output>5</output>

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

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

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

<result>50.24</result>