Marcus and three of his friends are guessing the radius of a circular pond. They read that the circumference is 157 ft, so they can use the equation 3.14⋅2r=157 to determine which of their guesses, which form the replacement set {20, 25, 30, 35}, is correct.
What is the radius of the pond?
20 ft
25 ft
30 ft
35 ft