Does the point (3,-1) lie on the circle (x+1)2 +(y-1)2=16?

Let’s see! Substituting 3 for x and -1 for y:

(3 + 1)^2 + (-1 - 1)^2 = 16
4^2 + (-2)^2 = 16
16 + 4 = 16
20 = 16

20 is clearly not equal to 16, so we know the point (3, -1) can’t lie on that circle.

Answer: r=4.5  feetexplanation: radius  r  is half of the diameter  d,⇒r=d2=92=4.5  feetidk i could be wrong