The sun shines down on a flagpole and on a mailbox at the same time casting shadows and making similar triangles. The mailbox is 4 ft tall and casts a shadow 3 ft long. The flagpole's shadow is 12 ft long. How tall is the flagpole?

To find the height of the flagpole, we can set up a proportion using the similar triangles formed by the flagpole and its shadow and the mailbox and its shadow.

Let x represent the height of the flagpole.

Using the proportion:

4/3 = x/12

Cross multiplying gives:

3x = 48

Dividing by 3 on both sides:

x = 16

Therefore, the flagpole is 16 ft tall.