Question 1045605
A diameter is cut into two segments.  Call them x and y.
3x=y, so this means  {{{3x+x=d}}} using d for DIAMETER.
{{{4x=d}}}
and if want r for radius, then {{{r=2x}}}.


Circumference information allows to say  {{{2pi*r=100}}}.

{{{pi*r=50}}}
{{{r=50/pi}}}-------radius is now solved.


Solve for the segments x and y.
{{{x=r/2}}}
{{{x=(50/pi)/2}}}
{{{highlight(x=25/pi)}}}------distance swimmer is from nearest side.
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solving for y is not necessary.


How far to swim to get to the center of the circle?
{{{highlight_green(r-x)}}}
and you can handle that expression to find the value.