Respuesta :

(4,1)  (-1, 2)
Distance = Square Root ( (X difference)^2 + (Y difference)^2 )

Distance = Square Root ((5^2) + (1 -2)^2)
Distance = Square Root ((25) + (-1^2))
Distance = Square Root  (25 +1)
Distance = Square Root  26
Radius = 5.0990195136