The upper base of a trapezoid is 14 cm, the lower base is 6 cm, and the height is 9 cm. What is its area in square centimeters?
一个梯形的上底是14厘米，下底是6厘米，高是9厘米，它的面积是多少平方厘米．
<gadget id="calculator">14 + 6</gadget>
<output>20</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">20 * (9/2)</gadget>
<output>90</output>

<result>90</result>