Solving Related Rates Problems Practice Test

A circle’s radius decreases at $1$ cm/s; what is $\dfrac{dA}{dt}$ when $r=7$, given $A=\pi r^2$?

A sphere’s radius increases at $2$ cm/s; what is $\dfrac{dV}{dt}$ when $r=3$ cm, given $V=\frac{4}{3}\pi r^3$?