Answer:
(a) 180°
(b) 180°
(c) transitive property of equality
(d) m∠3
(e) ∠3
Step-by-step explanation:
Given : ∠1 and ∠2 are supplementary and ∠2 and ∠3 are supplementary,
Prove : ∠1 ≅ ∠3 ,
By the definition of supplementary angles,
m∠1 + m∠2 = 180° and m∠2 + m∠3 = 180°,
Then, m∠1 + m∠2 = m∠2 + m∠3 by the transitive property of equality,
Subtract m∠2 from each sides,
m∠1 = m∠3,
or ∠1 ≅ ∠3
Hence, proved....