A small tree that is 5 feet tall casts a 3-foot shadow, while a building that is 45 feet tall casts a shadow in the same direction. Determine the length of the building's shadow.

9 feet
10 feet
15 feet
27 feet

10 feet

To solve this, you can set up a proportion using the heights and shadows of the tree and the building:

Tree height / Tree shadow = Building height / Building shadow
5 feet / 3 feet = 45 feet / x feet

Cross multiply to solve for x:
5 * x = 3 * 45
5x = 135
x = 135 / 5
x = 27

Therefore, the length of the building's shadow is 27 feet.