Question

Draw a plain scale to read miles for a map whose R.F. is `1/(10,00,000)`.

Answer 1

Given: R.F. = `1/(10,00,000)`

We want the scale to show distance in miles.

1 mile = 1.609 km = 160934 cm

1 cm on the map = 10,00,000 cm on the ground

= `(10,00,000)/(160934) ≈ 6.21` miles

Let’s take a round number:

Ground distance = 62.1 miles

Map length = `("Group Distance")/("Distance per cm") = (62.1)/(6.21) = 10` cm

Drawing the scale:

Draw a 10 cm long line.

Divide it into 5 equal parts, each = 2 cm.

Each part = `(62.1)/5 = 12.42` miles

Subdivide the first part (leftmost) into 4 sub-divisions, each = `(12.42)/4 = 3.1` miles

Labelling:

Start labeling from 0 to the right: 0, 12.4, 24.8, 37.2, 49.6, 62.1 miles

On the left of 0: 3.1, 6.2, 9.3, 12.4 miles