Question 594096
{{{drawing(400,3600/13,-3,9,-3,6,

red(locate(-1.5,3.3,"Y(?,?)"), locate(7.2,3.3,"W(?,c)"),

locate(1.7,0,"S(a,0)"),locate(4.8,0,"T(b,0)")),

line(-2,0,8,0), line(0,-2,0,5), locate(7.8,0,x), locate(.2,5,y),

red(line(2,0,0,3),line(5,0,7,3), line(0,3,7,3),line(2,0,5,0)) 

 )}}} 

The point Y must be the same distance above the x axis as the
point W(?,c).  So the y-coordinate of Y must be the same as the 
y-coordinate of W, so it is c also.  Also since Y is on the y-axis
its x-coordinate must be 0. So now we have:

{{{drawing(400,3600/13,-3,9,-3,6,

red(locate(-1.5,3.3,"Y(0,c)"), locate(7.2,3.3,"W(?,c)"),

locate(1.7,0,"S(a,0)"),locate(4.8,0,"T(b,0)")),

line(-2,0,8,0), line(0,-2,0,5), locate(7.8,0,x), locate(.2,5,y),

red(line(2,0,0,3),line(5,0,7,3), line(0,3,7,3),line(2,0,5,0)) 

 )}}} 

The origin is directly underneath Y, and S is "a" units right
of the origin.  Therefore by symmetry, a point on the x-axis
directly underneath W must be "a" units to the right of T(b,0),
So the point on the x-axis directly underneath W must be Z(b+a,0).
Let's draw in that point:

{{{drawing(400,3600/13,-3,9,-3,6,

red(locate(-1.5,3.3,"Y(0,c)"), locate(7.2,3.3,"W(?,c)"),

locate(1.7,0,"S(a,0)"),locate(4.8,0,"T(b,0)"),locate(7,.6,"Z(b+a,0)")),
circle(7,0,.1),
line(-2,0,8,0), line(0,-2,0,5), locate(7.8,0,x), locate(.2,5,y),

red(line(2,0,0,3),line(5,0,7,3), line(0,3,7,3),line(2,0,5,0)) 

 )}}}

Since W is directly above Z, W must have the same x-coordinate as Z,
so the coordinates of W are (b+a,c), So we have:

{{{drawing(400,3600/13,-3,9,-3,6,

red(locate(-1.5,3.3,"Y(0,c)"), locate(7.2,3.3,"W(b+a,c)"),

locate(1.7,0,"S(a,0)"),locate(4.8,0,"T(b,0)"),locate(7,.6,"Z(b+a,0)")),
circle(7,0,.1),
line(-2,0,8,0), line(0,-2,0,5), locate(7.8,0,x), locate(.2,5,y),

red(line(2,0,0,3),line(5,0,7,3), line(0,3,7,3),line(2,0,5,0)) 

 )}}}

Edwin</pre>