An Island on a map is measured to be 4cm across. The scale of the map is 4cm to 500m. How long is the island in km?

The island is 2km. If the scale is 1cm:500m we need to multiply both left and right sides by 4 to get to the 4cm that was measured. This gets us 4cm: 2000m . We now need to convert 2000m to km which gives us 2km. Notes: (1000m = 1km)