Statement - Reason
1. K is the midpoint of MJ - 1. Given
2. L is the midpoint of NJ - 2. Given
3. Angle MJK = Angle LJN - 3. Identity
4. Line segment LK is parallel to MN - 4. Triangle midsegment theorem
5. Angle JKL = Angle JMN, and Angle JLK = Angle JNMN - 5.Transversal
6. Triangle JKL is similar to Triangle JMN - 6. AAA similarity theorem
7. JM = 2JK - 7. Statement 1
8. MN=2KL - 9. Statement 7 and 6