If the side length of a square is reduced to 1:4 and the side length is 40 cm, what is the actual side length of the square?
一个正方形按1：4的比例尺缩小后的边长是40厘米，那么这个正方形的实际边长是多少厘米．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">40 / (1/4)</gadget>
<output>160</output>

<result>160</result>