Question

What would be the reasons for lines 3 and 4? A. Addition property; subtraction property B. Addition property; solve C. Substitution property; subtraction property D. Substitution property; prove

Answer 1

I chose

D. Substitution property; prove

Answer 2

C

Explanation:

We are given that angle 1 and angle 2 are supplementary angles.

`m\angle 1=128^(\circ)`

We have to find the reason for line 3 and 4.

1.Angle 1 and angle 2 are supplementary angles

`m\angle 1=128^(\circ)`

Reason:Given

2.
`m\angle 1+m\angle2=180^(\circ)`

Reason:Definition of supplementary angles.

3.
`128^(\circ)+m\angle 2=180^(\circ)`

Reason:Substitute property

4.
`m\angle 2=180-128=52^(\circ)`

Reason:Subtraction property of equality

Hence, option C is true.