One afternoon at 2:00, the shadow lengths of a flagpole and a big tree are 6 meters and 4 meters respectively. It is known that the flagpole is 15 meters high, how many meters is this big tree?
某天下午2：00，一根旗杆和一颗大树的影长分别为6米和4米．已知旗杆高为15米，这颗大树高多少米？
<gadget id="calculator">15 / 6</gadget>
<output>5/2 = around 2.5</output>

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

<result>10</result>