Xiao Ming measured the shadow length of the flagpole in the sun to be 4 meters, and at the same time measured the length of the 2-meter bamboo pole to be 40 cm. Please calculate the actual length of the flagpole.
小明在阳光下测得旗杆的影长为4米，同时测得2米的竹竿长40厘米，请你算一下旗杆的实际长度．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(1/4) * (2/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">2 / (1/10)</gadget>
<output>20</output>

<result>20</result>