A square with a side length of 4 decimeters is composed of two identical right-angled trapezoids, what is the area of one of the trapezoids in square decimeters?
一个边长4分米的正方形是由两个完全相同的直角梯形拼成的，其中一个梯形的面积是多少平方分米．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>