The Side-angle-side postulate states that if the pair of a corresponding sides and angles formed between these sides of two triangles are equal in measurement then these two triangle are said to be congruent.
As shown in figure 1 below:
In Δ HIJ and ΔKLM,
∠I = ∠L = 20° and HI = KL = 5 units
Since the ∠I lies between HI and IJ and ∠L lies between KL and LM, ∴ if IJ = LM then Δ HIJ and ΔKLM will be congruent by SAS postulate.