The height of a trapezoid is 6 cm, the upper base is 3 cm, and the lower base is 13 cm. What is the area in square centimeters?
一个梯形的高是6厘米，上底是3厘米，下底是13厘米，面积是多少平方厘米．
<gadget id="calculator">3 + 13</gadget>
<output>16</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">16 * 3</gadget>
<output>48</output>

<result>48</result>