1. $&\frac{\sf AD}{\sf DC}=\frac{\sf BE}{\sf EC}$&
1. given
2. $&\frac{\sf AD}{\sf DC} + {\sf1} = \frac{\sf BE}{\sf EC} + {\sf1}$&
2. addition property
3. $&\frac{\sf AD}{\sf DC} + \frac{\sf DC}{\sf DC} = \frac{\sf BE}{\sf EC} + \frac{\sf EC}{\sf EC}$&
3. property of proportion
4. $&\frac{\sf AD \, + \, DC}{\sf DC} = \frac{\sf BE \, + \, EC}{\sf EC}$&
4. addition of fractions
5. AC = AD + DC;
BC = BE + EC
5. segment addition postulate
6. $&\frac{\sf AC}{\sf DC}=\frac{\sf BC}{\sf EC}$&
6. substitution property
7.
7. reflexive property
8.
8. ♣
9.
9. ♦
10.
10. corresponding angles theorem