a.
<K = <M = 50 ...Opposite angels are congruent
<K + <L = 180...Consecutive angles are supplementary
50 + <L = 180 so <L = 180 - 50 = 130
<L = <N = 130...Opposite angels are congruent
50 + <N = 180 so <N = 180 - 50 = 130
b.
MN = LK = 7...Opposite sides are congruent
KN = LM = 10...Opposite sides are congruent