A cylindrical oil drum has a bottom diameter of 40 cm and a height of 50 cm. If each liter of diesel weighs 0.85kg, how many kilograms of diesel can this barrel hold?
一个圆柱形油桶，底面内直径为40cm，高50cm．如果每升柴油重0.85kg，这个油桶可装柴油多少kg？
<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>