1. $&\frac {\sf AD}{\sf DC} = \frac {\sf BC}{\sf EC}$&
1. given
2. $&\frac {\sf AD}{\sf DC} + {\sf 1} = \frac {\sf BC}{\sf EC} + {\sf 1}$&
2. addition property
3. $&\frac {\sf AD}{\sf DC} + \frac {\sf DC}{\sf DC} = \frac {\sf BC}{\sf EC} + \frac {\sf EC}{\sf EC}$&
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 + BC
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