The sum of the upper and lower bases of a trapezoid is 25 cm and the height is 8 cm. What is the area of this trapezoid.
一个梯形的上底与下底的和是25厘米，高是8厘米．这个梯形的面积是多少．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">25 * 4</gadget>
<output>100</output>

<result>100</result>