Question

A flagpole casts a shadow that is 20 feet long. If you are 5.5 feet tall and your shadow is 7 feet long ,how long is the flagpole

Answer 1

Figure for flagpole shadow:

Figure for your shadow:

You asume that the triangles are similar triangles.

In similar triangles the ratio between corresponding sides is the same:

$\frac{x}{5.5ft}=\frac{20ft}{7ft}$

You use the equation above to find the lenght of the flagpole (x):

$x=\frac{20ft\cdot5.5ft}{7ft}=\frac{110ft^2}{7ft}=15.71ft$The lenght of the flagpole is 15.71 feet