Answer:
r = 4.1231055
Step-by-step explanation:
So to do this, you need to find the distance between the two points:
(-7,1) and (1,3).
To do this, the distance or diameter (d) is equal to:
d = sqrt ((x2-x1)^2 + (y2-y1)^2)
In this case:
d = sqrt( (1 - (-7))^2 + (3 - 1)^2 )
d = sqrt( 8^2 + 2^2)
d = sqrt( 64 + 4)
d = sqrt( 68 )
The radius is half of the diameter, so:
r = 1/2 * d
r = 1/2 * sqrt( 68 )
r~ 4.1231055
