The upper base of a trapezoid is 1.5 meters, the lower base is 2.5 meters, and the height is 1.8 meters. What is its area in square meters?
一个梯形上底是1.5米，下底是2.5米，高是1.8米，它的面积是多少平方米．
<gadget id="calculator">1.5 + 2.5</gadget>
<output>4</output>

<gadget id="calculator">1.8 / 2</gadget>
<output>0.9</output>

<gadget id="calculator">4 * 0.9</gadget>
<output>3.6</output>

<result>3.6</result>