Answer:
See below
Step-by-step explanation:
∠KSM = ∠SKL + ∠KLS . . . . . external angle is the sum of opposite internal angles
In order for SM > KM (in contradiction to the hypothesis), we must have
∠MKS > ∠KSM . . . . . . . . . . . angle measures are in the same order as opposite side measures
However, ∠MKS ≅ ∠SKL (given), so SM > KM requires ...
... ∠SKL > ∠SKL + ∠KLS
For any triangle with non-zero area, ∠KLS > 0, so the above statement will be false (a contradiction)
Negating the hypothesis results in a contradiction, so we conclude the hypothesis is true: KM > SM.
