A cylindrical water bucket, the inner radius of its bottom surface is 2 decimeters, and the depth of the bucket is 5 decimeters. Now pour all the water filled with this bucket into another cuboid water tank. After pouring in, the water tank is still empty (1 /3). It is known that the bottom area inside the cuboid water tank is 15.7 square decimeters, how many decimeters is the height of the inner wall of this water tank?
一只圆柱体水桶，它的底面内半径为2分米，桶深为5分米，现将盛满这只水桶的水全部倒进另一只长方体水箱，倒进后水箱还空着(1/3)．已知长方体水箱内部的底面积是15.7平方分米，这只水箱的内壁高多少分米？
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">5 / 15.7 / (2/3)</gadget>
<output>0.477707</output>

<gadget id="calculator">3.14 * 4 * 0.477707</gadget>
<output>6</output>

<result>6</result>