The area of a trapezoid is 60 square meters, the height is 4 meters, the length of the upper base is 5.25 meters, how many meters is the length of the lower base?
一个梯形的面积是60平方米，高是4米，上底长5.25米，下底长多少米？
<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">60 * (1/2)</gadget>
<output>30</output>

<gadget id="calculator">30 - 5.25</gadget>
<output>24.75</output>

<result>24.75</result>