The inner diameter of the bottom surface of a cylindrical oil drum is 40 cm, and the height is 50 cm. If diesel oil weighs 0.85 kg per cubic decimeter, how many kg of diesel oil can be contained in this oil drum?
一个圆柱形油桶底面内直径40厘米，高50厘米，如果每立方分米柴油重0.85千克，这个油桶可装柴油多少千克？
<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">50 / 1_000</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">3.14 * 400 * (1/20) * 0.85</gadget>
<output>53.38</output>

<result>53.38</result>