If the area of a parallelogram made of two identical trapezoids is 60 square centimeters, what is the area of a trapezoid in square centimeters?
用两个完全一样的梯形拼成的平行四边形的面积是60平方厘米，那么一个梯形的面积是多少平方厘米．
<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<result>30</result>