The area of a trapezoid is 126 square meters, the upper base is 13 meters, and the lower base is 17 meters. What is the height of this trapezoid?
一个梯形面积是126平方米，上底是13米，下底是17米，这个梯形的高是多少米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">13 * (1/2)</gadget>
<output>13/2 = around 6.5</output>

<gadget id="calculator">17 * (1/2)</gadget>
<output>17/2 = around 8.5</output>

<gadget id="calculator">(13/2) + (17/2)</gadget>
<output>15</output>

<gadget id="calculator">126 / 15</gadget>
<output>42/5 = around 8.4</output>

<result>42/5 = around 8.4</result>