The perimeter of a rectangle is 80 cm, and the length is three times the width. What is the area of the rectangle in cm**2.
一个长方形的周长是80cm，长是宽的3倍，这个长方形的面积是多少cm**2．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">80 / 2 / 4</gadget>
<output>10</output>

<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<gadget id="calculator">30 * 10</gadget>
<output>300</output>

<result>300</result>