Given :
12 foot tall street light is making a 18 foot shadow at the same time a nearby building is making a 72 feet shadow.
To Find :
How tall is the building.
Solution :
Since, the time period is same so the angle angle of elevation is equal i.e the ratio of height of building is equal to height of shadow.
Let, height of building is h feet.
So,
Therefore, height of building is 48 feet.
Hence, this is the required solution.