(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A man 6 feet tall walks at a rate of 5 feet per second away from a light that is 15 feet above the ground. When he is 10 feet from the base of the light,

(A) at what rate is the tip of his shadow moving?

(B) at what rate is the length of his shadow changing?

2. Relevant equations

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3. The attempt at a solution

This is what I have so far...

dr/dt = 5 ft/sec

dx/dt = unknown

h = 10

Since the man is walking away, his shadow is getting bigger (right?).

for (A) I guess I'm suppose to find dx/dt since I already know what dy/dt is. But my question is which equation will work between the y and the x?

for (B) same question but my friend told me that it was a proportion; as in x/y = 6/15 but I'm not sure if that's right - even if it is, I'm still lost...

Help?

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# Homework Help: Related Rates

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