Analysis: Because 1 * 20 = 20, 2 * 10 = 20, 4 * 5 = 20, that is, 20 can be decomposed into the product of 1 and 20, the product of 2 and 10, and the product of 4 and 5. That is, square calligraphy works can be arranged in the following ways:
(1) 1 row 20 columns, (2)20 rows 1 column;
(3)2 rows 10 column, (4) 10 row and 2 columns;
(5)4 rows and 5 columns, (6)5 rows and 4 columns.
According to the perimeter formula, the perimeter = (length+width) * 2, and the perimeter of the rectangle is:
(1) 1 row 20 columns, (2)20 rows 1 column; It is 40 decimeters long (2 * 20 = 40 decimeters), 2 decimeters wide (1 * 2 = 2 decimeters) and 84 decimeters in circumference.
(3)2 rows 10 column, (4) 10 row and 2 columns; Assembled rectangle: 20 decimeters long (10 * 2 = 20 decimeters), 4 decimeters wide (2 * 2 = 4 decimeters) and 48 decimeters in circumference.
(5)4 rows and 5 columns, (6)5 rows and 4 columns. Assembled rectangle: length 10 decimeter (5 * 2 = 10 decimeter), width 8 decimeter (2 * 4 = 8 decimeter) and circumference 36 decimeter.
A: When the square calligraphy works are arranged in 4 rows and 5 columns, or 5 rows and 4 columns, the circumference of the overall pattern is the smallest.
Extended data:
To put small squares into a rectangle, we can first take the number of small squares as the product and find the corresponding two factors. For example, 1 * 20 = 20, 2 * 10 = 20, 4 * 5 = 20, that is, 20 can be decomposed into the product of 1 and 20,2 and 10,4 and 5.
Take these two factors as the length and width of the rectangle, calculate the corresponding perimeter according to the meaning of the question, and compare and choose the smallest perimeter.
The closer the length and width are, the shorter the circumference of the rectangle is.