A parallelogram nursery has a base of 50 meters and a height of 90 meters. What is its area in hectares?
一个平行四边形苗圃的底是50米，高是90米，它的占地面积是多少公顷．
<gadget id="calculator">50 * 90</gadget>
<output>4_500</output>

<gadget id="calculator">4_500 / 10_000</gadget>
<output>9/20 = around 0.45</output>

<result>9/20 = around 0.45</result>