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

A street light is on top of a 20-foot pole. A person who is 5 feet tall walks away from the pole at the rate of 5 feet per second. At what rate is the tip of the person's shadow moving away from the pole when he is 20 feet from the pole?

2. The attempt at a solution

20/5 = y/y-x (similar triangles)

y = 4x/3 (to solve for x)

im stuck here...

i also checked another solution i got here but i dont know how he got dy/dt = (6/9)*5

https://www.physicsforums.com/showthread.php?t=114901

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