A triangle and a parallelogram have the same area and height. If the base of the triangle is 9 cm, what is the base of the parallelogram?
三角形和平行四边形等面积等高，如果三角形的底是9厘米，那么平行四边形的底是多少．
<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<result>9/2 = around 4.5</result>