A triangle and a parallelogram have the same base and height, and the area of the triangle is known to be 20cm**2, so what is the area of the parallelogram in cm**2?
一个三角形与一个平行四边形等底等高，已知三角形的面积是20cm**2，那么平行四边形的面积是多少cm**2．
<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<result>40</result>