Reasoning

if ∠1 and ∠2 are complementary angles,

• then m∠1 + m∠2 = 90

• then m∠1 + m∠2 = 180

• then ∠1 and ∠2 are supplementary

• then ∠1 ≅ ∠2

if ∠1 and ∠2 are supplementary angles,

• then m∠1 + m∠2 = 90

• then m∠1 + m∠2 = 180

• then ∠1 and ∠2 are supplementary

• then ∠1 ≅ ∠2

if ∠1 and ∠2 are vertical angles,

• then m∠1 + m∠2 = 90

• then m∠1 + m∠2 = 180

• then ∠1 and ∠2 are supplementary

• then ∠1 ≅ ∠2

if ∠1 and ∠2 are a linear pair,

• then m∠1 + m∠2 = 90

• then ∠1 ≅ ∠2

• then ∠1 and ∠2 are supplementary

if R is between S and B, and S, R, and B are collinear,

• then SR + RB = SB

• then SR = RB

if R is the midpoint of segment SB,

• then SR + RB = SB

• then SR = RB

if S is on the interior of ∠BRM,

• then m∠BRS + m∠SRM = m∠BRM

• then m∠BRS = m∠SRM

• then ∠BRS ≅ ∠SRM

• then ∠BEC is a right angle

if ray RS bisects ∠BRM,

• then m∠BRS + m∠SRM = m∠BRM

• then m∠BRS = m∠SRM

• then ∠BEC is a right angle

if ∠1 and ∠2 are complementary angles, then m∠1 + m∠2 = 90

• Definition of Complementary Angles

• Definition of Supplementary Angles

• Definition of Vertical Angles

• Definition of Linear Pair

if ∠1 and ∠2 are supplementary angles, then m∠1 + m∠2 = 180

• Definition of Complementary Angles

• Definition of Supplementary Angles

• Definition of Vertical Angles

• Definition of Linear Pair