1) [tex]\overline{AB} \cong \overline{CD}[/tex], [tex]\overline{AD} \cong \overline{CB}[/tex], [tex]\overline{AX} \perp \overline{BD}[/tex], [tex]\overline{CY} \perp\overline{BD}[/tex] (given)
2) [tex]\overline{BD} \cong \overline{BD}[/tex] (reflexive property)
3) [tex]\triangle ABD \cong \triangle ACDB[/tex] (SSS)
4) [tex]\angle ADB \cong \angle CBY[/tex] (CPCTC)
5) [tex]\angle CYB[/tex] and [tex]\angle AXD[/tex] are right angles (perpendicular lines form right angles)
6) [tex]\triangle CYB[/tex] and [tex]\triangle AXD[/tex] are right triangles (a triangle with a right angle is a right triangle)
7) [tex]\triangle AXD \cong \triangle CYB[/tex] (HA)
8) [tex]\overline{AX} \cong \overline{CY}[/tex] (CPCTC)
