9. Cut a rectangular cardboard that is 90 cm long and 42 cm wide into small square pieces with integer centimeter sides and equal areas, without any remainder. The minimum number of pieces that can be cut is $\qquad$, and the total perimeter of all the square pieces cut in this way is $\qquad$ cm.
Analysis:

The number of small squares cut into 1 square centimeter is the maximum. To find the minimum number is to find the maximum side length of the square, which is the greatest common divisor of 90 and 42 -- 6. The side 90 can be cut into 15 pieces of 6, and 42 can be cut into 7 pieces of 6, making a total of 105 squares with an area of 36 each, and the perimeter is \(6 \times 4 \times 105 = 2520\).