There is a trapezoidal iron sheet, the upper base is 1.4 meters long, the lower base is 3.5 meters long, and the area is 4.9 square meters. What is the height of this iron sheet? (solution by equation)
有一块梯形铁皮，上底长1.4米，下底长3.5米，面积是4.9平方米，这块铁皮的高是多少？(用方程解)
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1.4 * (1/2)</gadget>
<output>0.7</output>

<gadget id="calculator">3.5 * (1/2)</gadget>
<output>1.75</output>

<gadget id="calculator">0.7 + 1.75</gadget>
<output>2.45</output>

<gadget id="calculator">4.9 / 2.45</gadget>
<output>2</output>

<result>2</result>