The scale of a map is the relationship between the distance on the map and the actual distance. In this case, the scale of the map is 1:4000, which means that 1 unit on the map represents 4000 units in the actual distance. To find the actual distance that is represented by 6.4 cm on the map, we need to convert the distance on the map to the same unit as the actual distance. Since 1 cm is equal to 0.01 m, 6.4 cm is equal to 6.4 * 0.01 = 0.064 m.
Now we can use the scale of the map to convert the distance on the map to the actual distance. We can set up the following proportion:
0.064 m / 1 = x / 4000
Where x is the actual distance in metres. Solving for x, we get:
x = 0.064 m * 4000 = 256 m
Therefore, the actual distance represented by 6.4 cm on the map is 256 m.