Question

Which proportion would you use to solve the following problem?

A map has a scale of 1 cm : 5 km. Determine how far apart two cities are if they are 4 cm apart on the map.
A.
B.
C.
D.

Answer 1

1/5 = 4/x

Explanation:

Each cm on the map represents 5 km. If it shows 4 cm apart of the map, you can use the proportion 1 cm : 5 km = 4 cm : x km.

Answer 2

20 km

Explanation:

We can use ratios to solve

1 cm 4 cm

-------- = ------------

5 km x km

Using cross products

1 * x = 4 * 5

x = 20

20 km