The measurement team measured the shadow length of a big tree to be 15 meters, and at the same time measured the shadow length of a 1.5-meter-high small tree next to it to be 1.2 meters. How tall is the big tree? (Solve using ratio method)
测量小组测得一棵大树的影长是15米，同时测的旁边一棵1.5米高的小树的影长是1.2米，大树高多少米？(用比例方法解答)
<gadget id="calculator">1.2 / 1.5</gadget>
<output>0.8</output>

<gadget id="calculator">15 / 0.8</gadget>
<output>18.75</output>

<result>18.75</result>