Circle Area Formula: A = πr²
First, lets find the radius of the circle (we can just divide the diameter by two).
42 / 2 = 21in.
Second, lets solve for the area.
A = π(21)²
A = π(441)
A = 1,384.74 inches.
Note that some questions ask for the answer to be written before pi is solved so if you need it then it can also be 441π.
Best of Luck!
