The sum of the upper and lower bases of a trapezoid is 40.5 cm, and the height is 1.2 cm. What is its area in square centimeters?
一个梯形的上下底之和是40.5厘米，高是1.2厘米，它的面积是多少平方厘米．
<gadget id="calculator">1.2 / 2</gadget>
<output>0.6</output>

<gadget id="calculator">40.5 * 0.6</gadget>
<output>24.3</output>

<result>24.3</result>