If two identical trapezoids are put together to form a square, and the height of the trapezoid is 4 cm, what is the area of each trapezoid in square centimeters?
两个完全一样的梯形拼成一个正方形，梯形的高是4厘米，那么每个梯形的面积是多少平方厘米．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

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

<result>8</result>