Find the radius of a circle with center at (4,1), if a chord of length 4 sqrt 2 is bisected at (7,4)
draw a segment from the circle's center to the point of bisection ... use the distance formula to find the length of this segment.
draw a radius from the center to one of the chord's endpoints.
you should now have a right triangle ... radius is the hypotenuse.
You have two of the three sides ... use Pythagoras.