A steel pipe has an outer diameter of 4 decimeters, an inner diameter of 3 decimeters, and a length of 5 meters. Each cubic meter of steel weighs 7.8 kilograms. How much does this steel pipe weigh in kilograms?
一根钢管，外直径4分米，内直径3分米，长5米，每立方米钢重7.8千克，这根钢管重多少千克？
<gadget id="calculator">0.4 / 2</gadget>
<output>0.2</output>

<gadget id="calculator">0.2 ** 2</gadget>
<output>0.04</output>

<gadget id="calculator">0.3 / 2</gadget>
<output>0.15</output>

<gadget id="calculator">0.15 ** 2</gadget>
<output>0.0225</output>

<gadget id="calculator">0.04 - 0.0225</gadget>
<output>0.0175</output>

<gadget id="calculator">3.14 * 0.0175 * 5 * 7.8</gadget>
<output>2.14305</output>

<result>2.14305</result>