The lower base of a trapezoid is twice as long as the upper base. If the upper base is extended by 8 centimeters, a parallelogram with an area of 80 square centimeters will be formed by connecting one of the vertices of the trapezoid. What is the area of the trapezoid in square centimetres.
一个梯形下底是上底的2倍，如果上底延长8厘米，连接梯形某一顶点就组成一个面积为80平方厘米的平行四边形．梯形面积是多少平方厘米．
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">8 + 16</gadget>
<output>24</output>

<gadget id="calculator">80 / 16</gadget>
<output>5</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">24 * (5/2)</gadget>
<output>60</output>

<result>60</result>