A cylindrical oil barrel is filled with oil, pour out the oil in the barrel (1/9), and there are 30 liters left, the height of the oil barrel is known to be 6.25 decimeters, what is the area of the bottom of the oil barrel in square decimeters ?
一个圆柱形油桶装满了油，把桶里的油倒出(1/9)，还剩下30升，已知油桶的高是6.25分米，油桶的底面积是多少平方分米？
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 - (1/9)</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">30 / (8/9)</gadget>
<output>135/4 = around 33.75</output>

<gadget id="calculator">(135/4) / 6.25</gadget>
<output>5.4</output>

<result>5.4</result>