The area of a trapezoid is 30cm**2, the sum of its upper and lower bases is 12cm, what is its height.
一个梯形的面积是30cm**2，它的上下底的和是12cm，它的高是多少．
<gadget id="calculator">2 / 12</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">30 * (1/6)</gadget>
<output>5</output>

<result>5</result>