Question 5(Multiple Choice Worth 1 points)

(01.07 MC)

Lines BC and ED are parallel. They are intersected by transversal AE, in which point B lies between points and E. They are also intersected by transversal EC. Angle ABC measures 70 degrees. Angle CED measures 30 degrees.

Given: line BC is parallel to line ED
m∠ABC = 70°
m∠CED = 30°

Prove: m∠BEC = 40°

Statement Justification
line BC is parallel to line ED Given
m∠ABC = 70° Given
m∠CED = 30° Given
m∠ABC = m∠BED Corresponding Angles Theorem
m∠BEC + m∠CED = m∠BED Angle Addition Postulate

m∠BEC = 40° Subtraction Property of Equality


Which of the following accurately completes the missing statement and justification of the two-column proof?
m∠BEC + 30° = 70°; Substitution Property of Equality
m∠BEC + 30° = 70°; Addition Property of Equality
m∠BEC + 40° = 70°; Substitution Property of Equality
m∠BEC + 40° = 70°; Addition Property of Equality