The sum of the area of the two rectangles is 81 square meters, the ratio of their length is 6:5, and the ratio of width is 2:3, then how many square meters is the area of the big rectangle?
大小两个长方形的面积和是81平方米，它们长的比是6：5，宽的比是2：3，则大长方形的面积是多少平方米？
<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">12 + 15</gadget>
<output>27</output>

<gadget id="calculator">81 / 27</gadget>
<output>3</output>

<gadget id="calculator">3 * 15</gadget>
<output>45</output>

<result>45</result>