Textbook Problem

In Exercise 11 and 12, provide the missing statements and reasons.

Given:	$\angle 1\cong \angle 2;$ $\angle 3\cong \angle 4$ $\angle \text{s}$ $2$ and $3$ are complementary
Prove:	$\angle \text{s}$ $1$ and $4$ are complementary

PROOF
Statements	Reasons
1. $\angle 1\cong \angle 3$ and $\angle 3\cong \angle 4$	1. ?
2. ? and ?	2. If two $\angle \text{s}$ are $\cong$, then their measures are equal.
3. $\angle \text{s}$ $2$ and $3$ are complementary	3. ?
4. ?	4. The sum of the measures of complementary $\angle \text{s}$ is $90$
5. $m\angle 1+m\angle 4=90$	5. ?
6. ?	6. If the sum of the measures of two angles is $90$, then the angles are complementary