The sum of the areas of a triangle and its parallelogram with the same base and height is 27 square centimeters. What is the area of this parallelogram.
一个三角形和与它等底等高的平行四边形的面积之和是27平方厘米．这个平行四边形的面积是多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">27 * (2/3)</gadget>
<output>18</output>

<result>18</result>