The area of a parallelogram is 42cm**2, what is the area of a triangle with the same base and the same height in cm**2.
一个平行四边形的面积是42cm**2，与它同底等高的三角形的面积是多少cm**2．
<gadget id="calculator">42 / 2</gadget>
<output>21</output>

<result>21</result>