The upper base of a trapezoid is 12 cm. If the upper base is extended by 3 cm, a parallelogram with an area of 120 cm2 is formed. What is the height of the original trapezoid in cm?
一个梯形的上底是12厘米，如果把上底延长3厘米就成了一个面积是120平方厘米的平行四边形，原来梯形的高是多少厘米．
<gadget id="calculator">12 + 3</gadget>
<output>15</output>

<gadget id="calculator">120 / 15</gadget>
<output>8</output>

<result>8</result>