Ascale model of a city has a scale of 1 cm : 2.5 km. two buildings in the model are 1.7 cm apart. to the nearest tenth of a kilometer, what is the actual distance between the buildings in the city

This is the concept of linear proportionality, we are required to calculate the actual length between two buildings which have a distance of 1.7 cm when drawn to scale of 1 cm: 2.5 km. This can be calculated as follows;
actual distance= (distance on the map)*(scale factor)
actual distance=1.7*2.5=4.25 km

The answer is 4.25 km