At 9 o'clock in the morning, Xiaoxiao measured that the shadow of a tree with a height of 1 meter was 1.2 meters long. At the same time, she measured the shadow of the school building to be 24 meters long. How high is this teaching building?
早上9时，笑笑量得一棵高1米的树的影子长1.2米．同时，她量得学校教学楼的影子长24米．这座教学楼高多少米？
<gadget id="calculator">1 / 1.2</gadget>
<output>0.833333</output>

<gadget id="calculator">0.833333 * 24</gadget>
<output>19.999992</output>

<result>19.999992</result>