The area of a trapezoid is 8.16, its upper base is 1.7 cm, and its lower base is 3.1 cm. What is its height?
一个梯形的面积是8.16，它的上底是1.7cm，下底是3.1cm，它的高是多少．
<gadget id="calculator">1.7 + 3.1</gadget>
<output>4.8</output>

<gadget id="calculator">2 / 4.8</gadget>
<output>0.416667</output>

<gadget id="calculator">8.16 * 0.416667</gadget>
<output>3.400003</output>

<result>3.400003</result>