1. 3AB = 7AD
1. given
2. $&\frac{\sf AB}{\sf AD}=\frac{\sf7}{\sf3}$&
2. division property
3. 3AC = 7AE
3. given
4. $&\frac{\sf AC}{\sf AE} = \frac{\sf7}{\sf3}$&
4. ♣
5. $&\frac{\sf AB}{\sf AD} = \frac{\sf AC}{\sf AE}$&
5. substitution property
6.
6. def. of vertical angles
7.
7. vertical angles theorem
8.
8. ♦