On the administrative region map of Yongchun with a scale of 1:3000000, the distance from Hengkou to Yongchun is 2.9 cm. Please do the math: how many kilometers is the distance from Hengkou to Yongchun.
在比例尺是1：3000000永春行政区域图上，横口至永春的距离是2.9厘米，请你算一算：横口至永春的相距多少千米．
<gadget id="calculator">1 / 3_000_000</gadget>
<output>1/3_000_000 = around 0</output>

<gadget id="calculator">2.9 / (1/3_000_000) / 100_000</gadget>
<output>87</output>

<result>87</result>