Thread: Another Related Rate Problem

Here is the text of my problem:

A boy is flying a kite at a height of 150ft. If the kite moves gorizontally away from the boy at 20ft/s, how fast is the string being paid out when the kite is 250ft from him?









Given:

• y=150ft
• x=250ft
• 

Find:

• 

Work:

• by the theorem of pythagoras:
  
  • 
• 

• 

• 

The book goves an answer of 16ft/s. Can someone give me a hint of where I might have gone astray? Thanks!

Originally Posted by dbakeg00

Here is the text of my problem:

A boy is flying a kite at a height of 150ft. If the kite moves gorizontally away from the boy at 20ft/s, how fast is the string being paid out when the kite is 250ft from him?



Given:

• y=150ft
• x=250ft
• 

Find:

• 

Work:

• by the theorem of pythagoras:
  
  • 
• 

• 

• 

The book goves an answer of 16ft/s. Can someone give me a hint of where I might have gone astray? Thanks!

The distance from the person is the hypotenuse not the adjacent side.



This should fix your problem.

ok, I see what you mean.

That gives me this triangle:
x=200
y=150
z=250

which now gives me:






Thanks for the help, appreciate it very much. These word problems are sometimes difficult for me to visualize if I'm not careful.