A square with a side length of 9 cm is surrounded by a piece of iron wire. If it is changed into a rectangle, the width of the rectangle is known to be 7 cm. Find the area of the rectangle.
用一根铁丝围成边长是9厘米的正方形，如果把它改围成一个长方形，已知长方形的宽是7厘米，求长方形的面积是多少．
<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">4 * (9/2)</gadget>
<output>18</output>

<gadget id="calculator">18 - 7</gadget>
<output>11</output>

<gadget id="calculator">11 * 7</gadget>
<output>77</output>

<result>77</result>