At 9 a.m. on Sunday, the sun was shining brightly, and the science and technology team of Class 1 of the Sixth Class was conducting measurement activities in the field. A bamboo pole with a length of 3 meters is erected on the ground, and the shadow length of the bamboo pole is measured to be 1.2 meters. At the same time, the shadow length of a water tower is measured to be 7.2 meters. According to this calculation, how many meters is the actual height of this water tower? (Answer with proportional knowledge)
星期天上午九时，阳光灿烂，六1班科技小组在野外进行测量活动．把一根长3米的竹竿直立在地上，测得竹竿的影长1.2米，同时测得一水塔的影长为7.2米．按这样计算，这座水塔的实际高度是多少米？(用比例知识解答)
<gadget id="calculator">3 * 7.2</gadget>
<output>21.6</output>

<gadget id="calculator">21.6 / 1.2</gadget>
<output>18</output>

<result>18</result>