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 in cm**2.
一个梯形的上底是5.8cm，下底是6.2cm，高是2.5cm，它的面积是多少cm**2．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">5.8 + 6.2</gadget>
<output>12</output>

<gadget id="calculator">(1/2) * 12 * 2.5</gadget>
<output>15</output>

<result>15</result>