1. be || cd 1. given
2. ∠a ≅ ∠a 2. reflexive property
3. ∠acd ≅ ∠abe 3. corresponding angles formed by parallel lines and a transversal are ≅.
∠adc ≅ ∠aeb 4. corresponding angles formed by parallel lines and a transversal are ≅.
5. δabe ∼ δacd 5. aa similarity postulate
6.
ac
ab
=
ad
ae
6. definition of similar triangles
7. ac = ab + bc, ad = ae + ed 7. segment addition postulate
8.
ab + bc
ab
=
ae + ed
ae
8. substitution
9.
ab
ab
+
bc
ab
=
ae
ae
+
ed
ae
9. addition
10.
bc
ab
=
ed
ae
10.

fill in the missing reason for the proof.
a) transitive property
b) subtraction property
c) sss similarity theorem
d) segment addition postulate