A parallelogram wheat field has a base of 200 meters, a height of 450 meters, and a total of 189 tons of wheat harvested. How many tons of wheat are harvested on average per hectare?
一块平行四边形麦地的底是200米，高是450米，共收小麦189吨．平均每公顷地收小麦多少吨？
<gadget id="calculator">450 / 10_000</gadget>
<output>9/200 = around 0.045</output>

<gadget id="calculator">200 * (9/200)</gadget>
<output>9</output>

<gadget id="calculator">189 / 9</gadget>
<output>21</output>

<result>21</result>