The perimeter of a rectangle is 28 centimeters. If its length and width are increased by 3 centimeters respectively, how many square centimeters will the area of the new rectangle be increased compared with the original rectangle?
一个长方形的周长是28厘米，如果它的长、宽都分别增加3厘米，那么得到的新长方形比原长方形的面积增加了多少平方厘米？
<gadget id="calculator">3 * 14</gadget>
<output>42</output>

<gadget id="calculator">42 + 9</gadget>
<output>51</output>

<result>51</result>