A cylindrical well with a circumference of 12.56 meters is 10 meters deep, and its usual water storage depth is 4/5 of the well depth. How many cubic meters of water does this well usually have?
一口周长是12.56米的圆柱形水井，它的深是10米，平时蓄水深度是井深的(4/5)，这口井平时的水量是多少立方米？
<gadget id="calculator">12.56 / 3.14 / 2</gadget>
<output>2</output>

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

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">10 * (4/5)</gadget>
<output>8</output>

<gadget id="calculator">3.14 * 4 * 8</gadget>
<output>100.48</output>

<result>100.48</result>