Help with a geometry question

We're doing proportions and triangles right now.

A man is 6 feet tall, is 12 feet away from a streetlight and the streetlight is 16 feet tall. How long is the man's shadow?

Hello

Here is the drawing

http://imageshack.us/photo/my-images/849…

ABE is the big triangle
DCE is the small one

The shadow is EC. Let's call it x

DC/AB = EC/EB

6/16 = x/(x+12)
Cross product
6(x+12) = 16x
6x + 72 = 16x
10x = 72
x = 7.2 ft ==> Answer

Hope it helps

Bye !

i disagree with the previous answer of 8 ft.


L
|
|
| 16'
| ........................................…
|.......................................…
|.......................................… 6'
|_________________________|_____________…
...................12'..................… x' ...............|

the corresponding sides of similar triangles are proportional, so

x compares to 6 in the same ratio as x + 12 compares to 16 or

....x...........x + 12
---------- = ----------------
....6..............16

now use the cross product theorem to get

16x = 6(x + 12) . multiply by 6 on left side

16x = 6x + 72 . subtract 6x from both sides

10x = 72 . divide both sides by 10

x = 7.2 feet. This is the length of the man's shadow.

good luck!

8 ft

ANSWER MY ?
http://answers.yahoo.com/question/index;…

here's the solution http://imgur.com/0vRF3
you can solve it by Thale's theory