The products of the height and the two bases of a trapezoid are 18 square centimeters and 25 square centimeters respectively. What is the area of this trapezoid in square centimeters?
一个梯形高与两底的乘积分别是18平方厘米和25平方厘米．这个梯形的面积是多少平方厘米？
<gadget id="calculator">18 + 25</gadget>
<output>43</output>

<gadget id="calculator">43 / 2</gadget>
<output>43/2 = around 21.5</output>

<result>43/2 = around 21.5</result>