5) Transitive property of equality
6) Addition property of equality
7) Subtraction property of equality
8) Division property of equality
9) Multiplication property of equality
10) Transitive property of congruence
11) Substitution property of equality
12) Addition property of equality [add XY to both sides then use segment addition postulate]
13) Subtraction property of equality [subtract XY from both sides then use segment subtraction postulate]
14) Angle addition postulate
15) Addition property of equality [add angle 2 to both sides then use angle addition postulate]
16) Transitive property of equality