Question

A two-story building measures 21 feet from the ground.Ascale model shows the building to be 3 inches tall. How many inches would an 84 foot building be in the model?

Answer 1

Answer: $12\ inches$

Step-by-step explanation:

Let be "x" the height inches (in the model) of a 84 foot building.

According to the information provided in the exercise, we know that the height of a two-story building is 21 feet and in the scale model its height is 3 inches.

Knowing this, we can set up the following proportion:

$\frac{3}{21}=\frac{x}{84}$

The final step is to solve for "x" in order to calculate its value. We get that this is:

$\frac{3}{21}=\frac{x}{84}\\\\(84)(\frac{3}{21})=x\\\\x=12$

Therefore,  an 84 foot building will be 12 inches tall in the model.