The length of the part measured on a precision drawing with a scale of 20:1 is 3 cm. What is the actual length of the part?
在一张比例尺为20：1的精密图纸上量得零件长3厘米，这个零件实际长是多少．
<gadget id="calculator">20 / 1</gadget>
<output>20</output>

<gadget id="calculator">3 / 20</gadget>
<output>3/20 = around 0.15</output>

<result>3/20 = around 0.15</result>