Question

HELPP!!!!

A 3-foot girl casts a shadow 7 feet long. She is standing next to a tree that casts a
28-foot shadow. How tall is the tree?

Answer 1

12 feet

Explanation:

This example can be solved using a proportion. The ratio between the height of the girl and her shadow is equal to the ratio of the height of the tree and its shadow.

Ratio of girl height to shadow length:
`(3)/(7)`

Ratio of the tree height and its shadow:
`(x)/(28)`

The proportion can be written:
`(3)/(7)=(x)/(28)`

The relationship between the denominators happens to be obvious, so this can be solved easily. 7 times 4 is 28, and since the ratios are equal, 3 times 4 must be X.

`3*4=12\\x=12`

The tree is 12 feet tall!