<span>If
we determine the distance from one point to the second point, we get the length of the diameter.
This is calculated through the equation,</span>
<span> D= sqrt ((x2 – x1)^2 + (y2 – y1)^2)</span>
Substituting
the known values,
<span> D = sqrt ((-1 – 3)^2 + (1 – 3)^2)</span>
<span> D = 4.47</span>
The
length of the radius is half that of the diameter. Hence, the radius is,
<span> R = 4.47 /2 = 2.236</span>
<span>Answer:
r = 2.24</span>
