Answer
Statements
4. m$\angle$1=m$\angle$2
5. $\angle$1≅$\angle$2
Reasons
1. Given
3. Substitution Property of Equality
Work Step by Step
Statement 1 is given in the problem. Statement 3 can be made by substituting 90$^{\circ}$ for m$\angle$2+m$\angle$3. Statement 4 is reached using the Subtraction property of Equality to subtract m$\angle3$ from both sides of the equation. Statement 4 is the desired conclusion that can be proven using the definition of congruent angles.