Answer:
Right angle
Explanation:
When two lines intersect, a linear pair is formed, two angles being linear pair means the sum of those two angles is 180°.
Now if ∠ABC and ∠CBD for a linear pair,
∴∠ABC + ∠CBD = 180°
also given that ∠ABC and ∠CBD are of equal measure
∴ ∠ABC + ∠ABC = 180°
⇒ ∠ABC = 90° = ∠CBD
∴ ∠ABC is right angle