Question 356974
proof:
angle 2 is congruent to angle 3 - given
let angle2=ange3= x...... result no.1
 angle1+angle 2 =90 - as its given they are complementary
therefore, angle1 +x= 90..... result no.2[ as we have assumed in result 1]
           angle3+angle4=90 - as its given they are complementary
therefore, x + angle4=90.... result no.3 [ as we have assumed in result 1]
therefore from results 2 and 3, we conclude that 
             angle1+x = angle4 +x
subtracting x from each side of te above eqaution,
               angle1 = angle 4
that is,
           angle1 congruent to angle4