On the design drawing with a scale of 1:400, the side length of a square flowerbed is 5 cm. What is the actual area of the garden in square meters?
在比例尺是1：400的设计图上，量的一个正方形花圃的边长是5厘米．这个花圃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">5 / (1/400) / 100</gadget>
<output>20</output>

<gadget id="calculator">20 * 20</gadget>
<output>400</output>

<result>400</result>