Question 1192419
<pre> 
Given: O is the midpoint of XY and of AB
Prove: XA ≅ BY

{{{drawing(2400/7,400,-6,6,-7,7,

line(-4,-6,4,6),line(-5,2,5,-2),

locate(0,0,O), locate(-4,-6,A), locate(5,-2,Y), locate(-5.2,2.6,X),
locate(3.95,6.6,B),



green(line(-5,2,-4,-6),line(5,-2,4,6)))}}} 

1. XO ≅ YO       |1. O is the midpoint of XY
2. ∠XOA ≅ ∠YOB   |2. vertical angles are congruent   
3. AO ≅ BO       |3. O is the midpoint of AB
4. ΔXOA ≅ ΔYOB   |4. side-angle-side    
5. XA ≅ BY       |5. corresponding parts of congruent triangles

Edwin</pre>