Question

The figure below shows triangle NRM with r2 = m2 + n2.



Ben constructed a right triangle EFD with legs m and n, as shown below.



He made the following table to prove that triangle NRM is a right triangle.

Statement
Reason
1. r2 = m2 + n2
Given
2. f2 = m2 + n2
Pythagorean Theorem
3. f2 = r2
Substitution
4. f = r
Square Root Property of Equality
5. Triangle NRM is congruent to triangle EFD
SSS Postulate
6. Angle NRM is a right angle
?
7. Triangle NRM is a right triangle
Angle NRM is a right angle

Which reas