The scale of a design drawing is 1:400. A rectangular hall in the drawing is 6 cm long and 4 cm wide. What is the actual area of the hall in square meters?
一张设计图得比例尺是1：400，图中的一个长方形大厅长6厘米，宽4厘米，这个大厅的实际面积是多少平方米？
<gadget id="calculator">1 / 400</gadget>
<output>1/400 = around 0.0025</output>

<gadget id="calculator">6 / (1/400) / 100</gadget>
<output>24</output>

<gadget id="calculator">4 / (1/400) / 100</gadget>
<output>16</output>

<gadget id="calculator">24 * 16</gadget>
<output>384</output>

<result>384</result>