Determine the RF on the scale:

A length of 3 km on the ground is presented via 6 cm length on a map. Determine the RF on the scale on that it has been drawn.

 RF = Length of drawing/ Length of object

 = 6 cm/(3 × 1000 × 100 cm)

= 1/(5 × 104)

Example 3

An area of 36 sq km on the ground is presented via an area of 144 sq cm on a map. Find out the RF of the scale for this map.

Now, instead of lengths, area has been provided and we will be committing a mistake whether we get the ratio of areas as RF is a ratio among lengths and not areas. Via a simple unitary process we recognize that 144 sq cm on the map represents 36 sq km on such ground. Getting square root on both the sides so we get 1 cm will represent ¼ sq km or ½ km such

RF = 1 cm/(0.5 × 1000 × 100 cm )

= 1/(0.5 × 105).