The sum of the upper and lower bases of the trapezoid is 10 meters, the area is 100 square meters, what is the height?
梯形的上下底的和是10米，面积是100平方米，高是多少．
<gadget id="calculator">100 / 10</gadget>
<output>10</output>

<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<result>20</result>