Question

The 4- inch radius of a circle is increasing at a rate of 2 inches per second. How fast is the area increasing?

Answer 1

A = πr^2
dA/dt = 2πr dr/dt
Now plug in your numbers

Answer 2

So im plugging in 2pie(4)? If so wjat do I do with the 2 inches per second ?

Answer 3

c'mon, man. In the first place, its <u>pi</u>, not pie.
They told you the radius is changing at 2in/s ... that is dr/dt
dA/dt = 2πr dr/dt = 2π*4*2 = 16π in/s

Answer 4

lol sorry im hungry. Thank you.