Answer:
7.By transitive property of equality
8.By substitution property
9.Subtraction property of equality
10.Converse of angles congruence postulate.
Explanation:
We are given that
, angle 2 and angle 3 are supplementary and angle 1 and angle 4 are supplementary.
We have to prove that
![\angle 1\cong\angle 3](https://img.qammunity.org/2020/formulas/mathematics/high-school/ec9v28u9c2gobh4byz2idvl0echw1kvprn.png)
We have to write missing statements in given proof.
1.
![\angle 2\cong\angle 4](https://img.qammunity.org/2020/formulas/mathematics/high-school/cbyswbcnnwqjp65hmt5nyr97clb8u2ihk5.png)
Given
2.
![m\angle 2=m\angle 4](https://img.qammunity.org/2020/formulas/mathematics/high-school/90p27wil5t3dh9q5o9drf73dxt5znisqnt.png)
Angle congruence postulate
3.Angle 2 and angle 3 are supplementary.
Given
4.
![m\angle 2+m\angle 3=180^(\circ)](https://img.qammunity.org/2020/formulas/mathematics/high-school/s18fekyl6ol4518d3epupyn25gub4caanb.png)
By definition of supplementary angles
5.Angle 1 and angle 4 are supplementary
Given
6.
![m\angle 1+m\angle 4=180^(\circ)](https://img.qammunity.org/2020/formulas/mathematics/high-school/z5eurbantsnqfg6622r68im8o8mtv4jeg9.png)
By definition of supplementary angles
7.
![m\angle 1+m\angle 4=m\angle 2+m\angle 3](https://img.qammunity.org/2020/formulas/mathematics/high-school/6n2e8tbub9idozpwk4e1s2cespn6p0qezf.png)
By transitive property of equality
8.
![m\angle 1+m\angle 4=m\angle 4+m\angle 3](https://img.qammunity.org/2020/formulas/mathematics/high-school/cf3oylc98njd8zx21e9qwx1ac20b9itu92.png)
By substitution property
9.
![m\angle 1=m\angle 3](https://img.qammunity.org/2020/formulas/mathematics/high-school/cqe0z2qck7d4fhtjvw5myj8w7dms0o0wzc.png)
Subtraction property of equality
10.
![m\angle 1\cong m\angle 3](https://img.qammunity.org/2020/formulas/mathematics/high-school/3tosw6eq0d75ph39l6c51edruukzzu9x85.png)
Converse of angle congruence postulate