Answer:
dA/dt = 169,56 in²/min
Step-by-step explanation:
We have a circular puddle and its area is:
A = π*r² (1) r is the radius of the circular puddle
Differentiating on both sides of the equation we get:
dA/dt = π*2*r*dr/dt (1)
In that expression we know
r = 9 inches and dr/dt = 3 in/min. Therefore plugging these values in equation (1)
dA/dt = π*2*9*3
dA/dt = 169,56 in²/min
