At the same time and at the same place, the shadow of a 3-meter-long bamboo pole is 12 meters long, and the shadow of a tree is 42 meters long. How tall is the tree?
在同一时间、同一地点，一根长3米竹竿影子长12米，一棵树的影子长42米，这棵树高多少米？
<gadget id="calculator">3 / 12</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) * 42</gadget>
<output>21/2 = around 10.5</output>

<result>21/2 = around 10.5</result>