Answer:
height of building is 48 ft.
Explanation:
This is a problem of ratio.
IN the given problem
ratio of object and its shadow will remain same for any object .
Given
A 12 ft tall street light is making an 18 ft shadow
ratio of
height of street light : height of shadow = 12:18 = 2:3
This ratio will be same for building as well
let the height of building be x ft
height of building : height of building shadow = x:72
x:72 will be equal to 2:3
x:72 = 2:3
x = 2/3*72 = 48
Thus, height of building is 48 ft.