∴AB∥CD,AD∥BC

∴∠BAD+∠CDA= 180，

∠ABC+∠DCB= 180，

∠ADC+∠BCD= 180

∫AE, BG, DE and FG are respectively

The angular bisector of ∠BAD∠ABC∠CDA∠BCD.

∴∠E= 180 -(∠EAD+∠EDA)

= 180 - 1/2(∠BAD+∠CDA)

= 180 -90 =90

Similarly, ∠ g = 90, ∠ ghe = ∠ CHD = 90.

∴ quadrilateral EFGH is a rectangle.