3. From 22 matches, form the outline of a rectangle with the largest possible area. Do not break the matches.

Translate the above text into English, keep the original text's line breaks and format, and output the translation result directly.
3. The sum of the length and width of a rectangle that can be formed using 22 matches is 11. By enumeration, we confirm that the rectangle with the largest area is $6 \times 5$.