Question 1036700
<pre><b>
{{{drawing(400,200,-6,6,-1,5,
locate(0,.2645,">"), locate(0,4.2645,">"),
line(-5,0,5,0),
line(5,0,3,4),
line(3,4,-3,4),
line(-3,4,-5,0),
line(-5,0,3,4),
line(-3,4,5,0),

line(2.41,1.07,2.59,1.43),
line(-2.41,1.07,-2.59,1.43),
locate(-5,0,"P"),
locate(5,0,"Q"),
locate(3,4.5,"R"),
locate(-3,4.5,"S"),
locate(-.1,3,"X") )}}}

1. &#916;PXQ is isosceles           1. PX = XQ        
2. &#8736;XPQ = &#8736;XQP                2. base angles of isosceles &#916;PXQ
3. &#8736;XPQ = &#8736;XRS                3. alternate interior angles when
                                  &#8741; lines PQ,SR are cut by 
                                  transversal PR.
4. &#8736;XQP = &#8736;XSR                4. alternate interior angles when
                                  &#8741; lines PQ,SR are cut by 
                                  transversal QS.
5. &#8736;XSR=&#8736;XQP=&#8736;XPQ=&#8736;XRS        5. Things = to = things are = to 
                                   each other, from steps 4,2,3

6. &#916;SXR is isosceles           6. Base angles equal
7. XS = XR                     7. Legs of isosceles &#916;SXR are equal. 

Edwin</pre></b>