If the upper base of a trapezoid is 5.8 cm, the lower base is 6.2 cm, and the height is 2.5 cm, what is its area?
如果一个梯形的上底是5.8厘米，下底是6.2厘米，高是2.5厘米，那么它的面积是多少．
<gadget id="calculator">5.8 + 6.2</gadget>
<output>12</output>

<gadget id="calculator">2.5 / 2</gadget>
<output>1.25</output>

<gadget id="calculator">12 * 1.25</gadget>
<output>15</output>

<result>15</result>