The diameter of a tree was 16 in. During the following year, the circumference increased 2 in. About how much did the tree's diameter increase? About how much did the tree's cross-section area change? The tree's diameter increased by |in. (Simplify your answer. Type an integer or decimal rounded to four decimal places as needed.) The estimated change in area is ]in.2. (Simplify your answer. Type an exact answer. Type an integer or a decimal.)