Question

Find the radius of the circle who centre is (3,2) and passes through (-5,6)

Answer 1

Using the distance formula we get
Root 80 as the radius

Answer 2

The radius is the distance between circumference and centre weknow.

the radius r^2=(-5-3)^2+(6-2)^2
=(-8)^2+(4)^2
=64+16
=80
if r^2=80 then r= √80=4√5(positive because distance cannot be negative).