rectangle has a perimeter of 45 cm and its length is twice its width. What is the area of this rectangle in square centimeters?
一个长方形的周长是45厘米，长是宽的2倍．这个长方形的面积是多少平方厘米？
<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">45 / 2 / 3</gadget>
<output>15/2 = around 7.5</output>

<gadget id="calculator">(15/2) * 2</gadget>
<output>15</output>

<gadget id="calculator">15 * (15/2)</gadget>
<output>225/2 = around 112.5</output>

<result>225/2 = around 112.5</result>