A cylindrical tin bucket is half filled with water. After pouring out 20% of the water in the bucket, there are 6.28 liters left. The circumference of the bottom of the oil barrel is 62.8 cm. How many decimeters is the height of the oil barrel?
一个圆柱体的铁皮水桶，装了半桶水，把桶里的水倒出20%后，还剩6.28升，油桶底面周长是62.8厘米，油桶高是多少分米？
<gadget id="calculator">62.8 / 3.14 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

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

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/2) * (4/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1_000 / 314 / (2/5) / 10</gadget>
<output>125/157 = around 0.796178</output>

<gadget id="calculator">6.28 * (125/157)</gadget>
<output>5</output>

<result>5</result>