[MA]:
r(t) = 3t ; Where 'T' represents the time in minutes and 'r' represents how far the paint is spreading
A(r) = πr²
Part A:
A[r(t)} = π (3t)² = 3.14 * 9t² = 28.26t²
Part B:
r(10) = 3(10) = 30
A(r) = 3.14 * 30² = 3.14 * 900 = 2,826 square units.
Writer's note: Hope this helps!
[xArtsy]