A trapezoid has an upper base and a height of 1.5 meters and a lower base twice the height, what is its area in square meters?
一个梯形，上底和高都是1.5米，下底是高的2倍，它的面积是多少平方米．
<gadget id="calculator">1.5 * 2</gadget>
<output>3</output>

<gadget id="calculator">1.5 + 3</gadget>
<output>4.5</output>

<gadget id="calculator">1.5 / 2</gadget>
<output>0.75</output>

<gadget id="calculator">4.5 * 0.75</gadget>
<output>3.375</output>

<result>3.375</result>