Answer:
Given : JKLM is a rectangle.
Prove: JL ≅ MK
Since, by the definition of rectangle all angles of rectangles are right angle.
Thus, In rectangle JKLM,
∠ JML and ∠KLM are right angles.
⇒ ∠ JML ≅ ∠KLM
Since, JM ≅ KL (Opposite sides of rectangles are congruent)
ML ≅ ML ( Reflexive )
Thus, By SAS congruence postulate,
Δ JML ≅ Δ KLM
⇒ JL ≅ MK ( because corresponding parts of congruent triangles are congruent)
Hence proved.