20) [tex]\overline{AC} \cong \overline{AC}[/tex] by the reflexive property, so SSS
21) [tex]\overline{CD} \cong \overline{CD}[/tex] by the reflexive property, so ASA
22) [tex]\overline{CE} \cong \overline{CB}, \overline{AC} \cong \overline{CD}[/tex] by the definition of a midpoint and [tex]\angle 1 \cong \angle 2[/tex], so SAS
23) [tex]\overline{AC} \cong \overline{AC}[/tex] by the reflexive property, so ASA
