A flagpole casts a 16-foot shadow at the same time a 4-foot pole casts a 5-foot shadow. How tall is the flagpole?

Set up a proportion:

The 4 foot pole casts a 5 foot shadow is written as 4/5

Let the height of the flagpole = x.

The flag pole casts a 16 foot shadow so it is written as X/16

Now set the two proportions equal to each other:

4/5 = X/16

Solve for X by cross multiplying:

5X = 64

Divide both sides by 5:

X = 64/5

X = 12.8

The flag pole is 12.8 feet tall.