Question

If the point (4, 4) is the center of a circle and the point (2, 3) lies on that circle, what is the circle's radius?

Answer 1

You need to use the distance formula which is - √(x1-x2)^2 + (y1-y2)^2
fill it in with the given points - √(4-2)^2 + (4-3)^2
simplify - √2^2 + 1^2
               √4 + 1
               √5
so r = √5
hope that helps :)