A piece of parallelogram glass has a base of 25.6 cm and is 2.9 cm shorter than three times its height. Find the area of this glass.
一块平行四边形的玻璃，底是25.6厘米，比高的3倍短2.9厘米，求这块玻璃的面积．
<gadget id="calculator">25.6 + 2.9</gadget>
<output>28.5</output>

<gadget id="calculator">28.5 / 3</gadget>
<output>9.5</output>

<gadget id="calculator">25.6 * 9.5</gadget>
<output>243.2</output>

<result>243.2</result>