square steel is 1.5 meters long, and its cross section is a square with a side length of 4 cm. It is known that the mass of square steel per cubic decimeter is 7.8 kg. What is the mass of this square steel in kilograms?
一根方钢长1.5米，它的横截面是一个边长为4厘米的正方形，已知每立方分米的方钢的质量是7.8千克，这根方钢的质量是多少千克．
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1.5 * 10</gadget>
<output>15</output>

<gadget id="calculator">(2/5) * (2/5) * 15 * 7.8</gadget>
<output>18.72</output>

<result>18.72</result>