Solving Related Rates Problems Practice Test

A point moves on $x^2+y^2=25$ with $\dfrac{dx}{dt}=4$. When $x=3$ and $y=4$, what is $\dfrac{dy}{dt}$?

A streetlight is 15 ft tall; a 6-ft person walks away at 5 ft/s. When the person is 10 ft from the pole, how fast is the shadow lengthening?