12 / 20

Determine the two smallest map scales, given the following:

A) 1:500 000
B) 10 cm = 10 NM
C) 5 inch = 10 NM
D) 1:110 000

  • A
    A) and B)
  • B
    A) and D)
  • C
    C) and D)
  • D
    B) and C)

Scale of the chart shows the ratio of the given length on the flat chart compared to the Earth’s distance that the given length on the chart represents.

When comparing scales, the following is true:

  • The greater the denominator, the smaller the scale.
  • The smaller the denominator, the greater the scale.

The first step includes converting into fractions the scales which aren’t expressed as fractions.


MAP B: 10 cm = 10 NM

10 cm on the map represents 1 852 000 cm on the Earth (note: 1 NM = 1 cm 185200)
1 cm on the map represents “X” cm on the Earth

  • X = (1 852 000) / 10 cm = 185 200 cm
  • Scale = 1 : 185 200

MAP B: 5 in = 10 NM

12.7 cm (5 in x 2.54 cm) on the map represents 1 852 000 cm on the Earth (note: 1 NM = 1 cm 185200)
1 cm on the map represents “X” cm on the Earth

  • X = (1 852 000) / 12.7 cm = 145 827 cm
  • Scale = 1 : 146 000

Scales order (ascending order):
1 : 500 000 (A) => 1 : 185 200 (B) => 1 : 146 000 (C) => 1 : 110 000 (D)

Your Notes (not visible to others)



This question has appeared on the real examination, you can find the related countries below.