A parallelogram with a base of 0.4m has the same area as a square with a side length of 1.8m. What is the height of the parallelogram?
一个底是0.4m的平行四边形和边长是1.8m的正方形面积相等，这个平行四边形的高是多少？
<gadget id="calculator">1.8 / 0.4</gadget>
<output>4.5</output>

<gadget id="calculator">1.8 * 4.5</gadget>
<output>8.1</output>

<result>8.1</result>