Answer:
Explanation:
∠ABD ≅ ∠BDE..... (given).... (1)
m∠ABD + m∠CBD = 180°... (straight line ∠'s)... (2)
From equations (1) & (2)
m∠BDE + m∠CBD = 180°....(3)
m∠BDE + m∠CDB = 180°... (straight line ∠'s)... (4)
From equations (3) & (4)
m∠BDE + m∠CBD = m∠BDE + m∠CDB
m∠CBD ≅ m∠CDB.. (Proved)