The area of a trapezoid is 30 square centimeters, its upper base is 7 cm, and its lower base is 5 cm. What is its height in cm?
一个梯形的面积是30平方厘米，它的上底是7厘米，下底是5厘米，它的高是多少厘米．
<gadget id="calculator">7 + 5</gadget>
<output>12</output>

<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>