SOLUTION: A man is walking away from a lamppost with a light source 6 m above the ground. The man is 2 m tall. How far from the lamppost is the man when his shadow is 5 m long?

Algebra ->  Trigonometry-basics -> SOLUTION: A man is walking away from a lamppost with a light source 6 m above the ground. The man is 2 m tall. How far from the lamppost is the man when his shadow is 5 m long?      Log On


   

Question 355076: A man is walking away from a lamppost with a light source 6 m above the ground. The man is 2 m tall. How far from the lamppost is the man when his shadow is 5 m long?
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = distance of the man from the base of the lamppost.
Then x + 5=distance of the tip of the man's shadow from the base of the lamppost. Then by a direct application of similar triangles,
%28x+%2B+5%29%2F6+=+5%2F2.
After cross-multiplication, 2%28x%2B5%29+=+30.
x%2B5+=+15
x+=+10.
The man is 10 m away from the base of the lamppost.