Uncle Wang is going to plant saplings around a rectangular land, which is 90 meters long and 15 meters wide. If the length of the rectangle is changed to 45 meters, what is the width in meters to keep the area constant?
王大伯准备围一块长方形的地种植树苗，这块地的长是90米，宽是15米．如果长方形地的长改为45米，要使面积大小不变，宽应该是多少米．
<gadget id="calculator">15 / 45</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">90 * (1/3)</gadget>
<output>30</output>

<result>30</result>