Two parallelograms with the same area, one with a base of 12cm and a height of 4.5cm, and the other with a height of 6cm, what is the base in cm?
两个面积相等的平行四边形，一个底是12cm，高是4.5cm，另一个高是6cm，底是多少cm．
<gadget id="calculator">4.5 / 6</gadget>
<output>0.75</output>

<gadget id="calculator">12 * 0.75</gadget>
<output>9</output>

<result>9</result>