The school has a triangular labor and technical activity base. On the school plan with a scale of 1:400, its base is 4 cm and its height is 2.5 cm. What is the actual area of this land in square meters?
学校有一块三角形的劳技活动基地，在比例尺为1：400的学校平面图上，量得它的底是4厘米，高是2.5厘米，这块地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">4 / (1/400) / 100</gadget>
<output>16</output>

<gadget id="calculator">2.5 / (1/400) / 100 / 2</gadget>
<output>5</output>

<gadget id="calculator">16 * 5</gadget>
<output>80</output>

<result>80</result>