Answer:
A ≈ 346.36
Step-by-step explanation:
To find the answer, you must use the formula, A=πr²
Since only the diameter was provided, you need to divide it by 2 to find the radius. 21 divided by 2 equals 10.5, so that will be your radius.
Another formula that can be used while using only the diameter would be A= 1/4 π d²
