Answer:
Part A:
Setting up the problem: A[r(t)] = π (4t)^2
= Multiplying: A[r(t)] = 3.14 x 16t^2
= Solving/Answer: A[r(t)] = 50.24t^2
Part B: Area after 4 min of spilling = t=4
= r (4)= 4x4 =16
= Setting up the problem: A(16) = 3.14 x 16^2
= Multiplying: A(16)= 3.14 x 256
= Solving/Answer: A(16) = 803.84
= The spilled area of milk after 4 min is 803.84.