A trapezoidal billboard has an area of 2.4 square meters, an upper base of 1.5 meters and a height of 1.2 meters. How long is the lower base in meters?
一块梯形广告牌，面积是2.4平方米，上底是1.5米，高是1.2米，下底长多少米？
<gadget id="calculator">2 / 1.2</gadget>
<output>1.666667</output>

<gadget id="calculator">2.4 * 1.666667</gadget>
<output>4.000001</output>

<gadget id="calculator">4.000001 - 1.5</gadget>
<output>2.500001</output>

<result>2.500001</result>