A hollow steel pipe is 2 meters long, with an inner diameter of 10 cm and an outer diameter of 20 cm. If each cubic centimeter of steel weighs 7.8 grams, how much does the steel pipe weigh in kilograms?
一根空心钢管长2米，内直径是10厘米，外直径是20厘米，如果每立方厘米的钢材重7.8克，这根钢管重多少千克？
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">100 - 25</gadget>
<output>75</output>

<gadget id="calculator">7.8 / 1_000</gadget>
<output>0.0078</output>

<gadget id="calculator">3.14 * 75 * 200 * 0.0078</gadget>
<output>367.38</output>

<result>367.38</result>