1. ABCD is a kite
1. given
2. AB ≅ BC
2. def. of kite
3. AD ≅ CD
3. def. of kite
4. BD ≅ BD
4. reflexive property
5. △BDA ≅ △BDC
5. SSS
6. ∠ABD ≅ ∠CBD
6. CPCTC
7. BE ≅ BE
7. reflexive property
8. △BEA ≅ △BEC
8. SAS
9. ∠BEA ≅ ∠BEC
9. CPCTC
10. m∠BEA = m∠BEC
10. def. of congruent
11. ∠BEA and ∠BEC are a linear pair
11. def. of linear pair
12. m∠BEA + m∠BEC = 180°
12. angle addition postulate
13. m∠BEC + m∠BEC = 180°
13. substitution property
14. 2(m∠BEC) = 180°
14. addition
15. m∠BEC = 90°
15. division property
16. m∠BEA = 90°
16. substitution property
17. AC ⊥ BD
17. def. of perpendicular