A cylinder of steel is 200 cm long and has a cross-sectional radius of 2 cm. If the steel weighs 7.8 grams per cubic centimeter, how many grams does this piece of steel weigh?
一根圆柱形钢材，长200厘米，横截面的半径是2厘米．如果每立方厘米钢材重7.8克，这段钢材重多少克？
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4 * 200</gadget>
<output>2_512</output>

<gadget id="calculator">2_512 * 7.8</gadget>
<output>19_593.6</output>

<result>19_593.6</result>