If the area of a parallelogram is 80 square decimeters, what is the area of a triangle with the same base and height as it?
一个平行四边形的面积是80平方分米，与它等底等高的三角形的面积是多少平方分米．
<gadget id="calculator">80 / 2</gadget>
<output>40</output>

<result>40</result>