A triangle and a parallelogram have the same area and height, and the base of the triangle is 30 cm. What is the base of the parallelogram in cm?
一个三角形和一个平行四边形的面积相等，高相等，三角形的底是30厘米，平行四边形的底是多少cm．
<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<result>15</result>