A cylindrical oil drum has a diameter of 40 cm and a height of 50 cm measured from the inside. If 1L of diesel weighs 0.85kg, how many kilograms of diesel can this barrel hold?
一个圆柱形油桶，从里面测量直径是40cm，高是50cm．如果1L柴油重0.85kg，那么这个油桶可以装多少千克柴油？
<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">0.85 * 3.14 * 400 * (1/20)</gadget>
<output>53.38</output>

<result>53.38</result>