On a drawing with a scale of 1:1,000,000, the length of a rectangular piece of land is 4 cm and the width is 2.5 cm. What is the actual area of the land in square kilometers?
在比例尺是1：1000000的图纸上，量得一块长方形地的长是4厘米，宽2.5厘米，这块地的实际面积是多少平方千米
<gadget id="calculator">1 / 1_000_000</gadget>
<output>1/1_000_000 = around 0.000001</output>

<gadget id="calculator">4 / (1/1_000_000) / 100_000</gadget>
<output>40</output>

<gadget id="calculator">2.5 / (1/1_000_000) / 100_000</gadget>
<output>25</output>

<gadget id="calculator">40 * 25</gadget>
<output>1_000</output>

<result>1_000</result>