A triangle and a parallelogram have the same base and the same area. The height of the parallelogram is 20 centimeters. What is the height of the triangle in centimeters?
一个三角形与一个平行四边形的底相等，面积也相等，平行四边形的高是20厘米，三角形的高是多少厘米．
<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<result>40</result>