On a globe with a scale of 1:50000000, the length of the equator is measured to be about 80 cm. What is the length of the earth's equator in kilometers?
一个比例尺为1：50000000的地球仪上，量得赤道长约80厘米，则地球赤道长约为多少千米
<gadget id="calculator">1 / 50_000_000</gadget>
<output>1/50_000_000 = around 0</output>

<gadget id="calculator">80 / (1/50_000_000) / 100_000</gadget>
<output>40_000</output>

<result>40_000</result>