Step-by-step explanation:
The attached figure shows two triangles AOB and MON.
In triangles AOB and MON,
AB = MN (Given )
∠AOB = ∠MON (vertically opposite angles)
∠O = ∠O (common)
∴ ΔAOB ≅ Δ MON (ASA)
Angle-side-angle is the postulate that can be used to prove that two triangles are congruent.
