## anonymous 5 years ago A street light is mounted at the top of a 14 ft tall pole. A woman 6 ft tall walks away from the pole with a speed of 6 ft/sec along a straight path. How fast is the tip of her shadow moving when she is 45 ft from the base of the pole?

1. anonymous

use similar triangles. create two similar triangles based on the information tehn take the derivative

2. anonymous

i dont understand how to do that

3. anonymous

check out this website and go to example 2, it has a similar question with different numbers =) http://www.math.wfu.edu/tutorials/Math111/RelatedRates.pdf

4. bahrom7893

okay carra i will solve it, im done with my hw

5. bahrom7893

For the answer try 9/2 (ft/sec) , let me know whether it is correct. If it is, I will post the solution.

6. anonymous

7. bahrom7893

try 4.5

8. anonymous

no

9. bahrom7893

k let me see if i did anythinig wrong, brb

10. bahrom7893

can you double check the question?

11. anonymous

question is correct

12. bahrom7893

okay, let me check my work again

13. bahrom7893

can you try 4/3 or 1.3

14. anonymous

no i sorry

15. anonymous

hey

16. anonymous

im on the case

17. anonymous

do you mind, i will use twiddla

18. anonymous
19. anonymous

click on that

20. bahrom7893

Okay so cantorset, this is what im doing: y/6 = (y+x)/14 => look at that in terms of similar triangles. Cross multiply and simplify: 14y = 6x + 6y 14(dy/dt)=6(dx/dt) + 6(dy/dt) 8 d(y/dt) = 6 (dx/dt) 8(dy/dt) = 6 * 6 8(dy/dt) = 36, solve for dy/dt = 9/2. What am I doing wrong?

21. anonymous

its a whiteboard

22. bahrom7893

carra try 10.5

23. bahrom7893

24. bahrom7893

http://i53.tinypic.com/o6i8b7.jpg there's the screen

25. bahrom7893

i gtg now, bbl