Explanation
Correct answer: C.
Choice C is correct. The area of a circle with radius is given by the formula . Thus, a circle with radius has area , which can be rewritten as . The area of a square with side length is given by the formula . Thus, if a square has the same area as a circle with radius , then . Since the side length of a square must be a positive number, taking the square root of both sides of gives . Using the properties of square roots, can be rewritten as , which is equivalent to . Therefore, .
Desmos solution:
Note: The positive fitted side length 3.5449 matches 2√π.
Enter in Desmos:
Reviewed and rewritten by CookSAT
Why the other choices are wrong
Choice A
Choice A is incorrect. The side length of the square isn't equal to the radius of the circle.
Choice B
Choice B is incorrect and may result from incorrectly simplifying the expression .
Choice D
Choice D is incorrect and may result from incorrectly simplifying the expression .