Question 1085416
Solving for y, UV has the equation {{{ y = (5/2)x - 7/2 }}} 

Using the above, we can plug in x=3 in order to find r:

       y = (5/2)(3) - 7/2 
       y = 15/2 - 7/2 = 8/2 = 4

So r=4, or equivalently, V is at (3,4).

Let the line MN be the perpendicular bisector of UV, and let M be the midpoint of UV.

Line MN has slope -2/5   (for y=mx+b, a line perpendicular Y=MX+B  will always have slope M=-1/m).
So far for MN we have  {{{ y  = -(2/5)x + b }}}

We just need b.  
To find b, we need M:   M is at the midpoint of UV:  ( {{{ (3+1)/2 }}} , {{{ (4 + (-1)) / 2 }}} )  or 
( {{{ 2 }}} , {{{3/2 }}} )

Now  plug in x & y and solve for b:   {{{ 3/2 = (-2/5)(2) + b }}} —> {{{ b = 3/2 + 4/5 = 15/10 + 8/10 = 23/10 }}}

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Ans:  The perpendicular bisector of UV has equation  {{{ highlight_green(y = (-2/5)x + 23/10) }}}