Since the length and width of the pictures are given in cm, let's convert all lengths to cm.
Remember that 1 m = 100 cm
3.6 m = 360 cm
1.8 m = 180 cm
The area of a rectangle is A = LW. The area of the board is
A = LW = 360 cm * 180 cm = 64,800 cm^2
The area of each picture is 6 cm * 6 cm = 36 cm^2
To see how many pictures fit in the board, we divide the area of the board by the area of one picture.
(64,800 cm^2)/(36 cm^2) = 1,800
Answer: 1,800 pictures