A triangle and a parallelogram have the same base and same height, the area of the parallelogram is 84cm**2, what is the area of the triangle dm**2.
一个三角形和一个平行四边形同底等高，平行四边形面积84cm**2，三角形面积是多少dm**2．
<gadget id="calculator">84 / 2</gadget>
<output>42</output>

<result>42</result>