What is the area of an circle when its 4 inches in diameter?

Answer 1

d = 4 so r = 2 so area = 4 x pi

umm actually, you have it right, but ill explain it a bit more. since we know the diameter is the length across the whole circle, and the radius is the length from the middle to the outside(making it half of the diameter) and we know area of a circle can be found using the formula area= pi(r)squared, you would divid the diameter in half to get the radius, which in this case is 2, and plug it in, so area=2 squared times pi, which is equal to 4pi. (use the symbol for pi though) some teacher prefer you leave it as 4pi, but others want only an approximation, not an exact answer since pi is a number that does not terminate, so depending on that, you could put 3.14 in for pi and multiply that to get an approx. answer.