Cut a 2-meter-long section from a cylindrical steel with a cross-sectional diameter of 2 centimeters, and the steel weighs 7.8 kilograms per cubic decimeter. How many kilograms does the cut piece of steel weigh?
从一根横截面直径是2厘米的圆柱形钢材上截下2米长的一段，每立方分米钢重7.8千克，截下的这段钢材重多少千克？
<gadget id="calculator">2 / 10 / 2</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) ** 2</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">3.14 * (1/100) * 2 * 10 * 7.8</gadget>
<output>4.8984</output>

<result>4.8984</result>