According to the formula of distance/actual distance = scale on the map and the formula of deformation calculation.

Note: to find the distance on the map, you must first calculate the unit; Finding the actual distance is to calculate the unit first.

Question 5:1900km =19000000cm.

190000000x (1/4000000) = 4.75cm.

Question 6: 3.4÷ (1/5000000) =17000000cm =170km.