What is the reason for Statement 3 of the two-column proof? Linear Pair Postulate

Definition of complementary angles

Angle Addition Postulate

Definition of angle
Given: the measure of angle J M K equals 52 degrees. The measure of angle K M L equals 38 degrees. Prove: angle J M L is a right angle. Art: Three rays M L, M K, and M J share an endpoint M. Ray M K forms a bisector. The bisector divides angle J M L into two parts labeled as J M K and K M L.

Statements Reasons
1. m∠JMK=52° Given
2. m∠KML=38° Given
3. m∠JMK+m∠KML=m∠JML
4. 52°+38°=m∠JML Substitution Property of Equality
5. 90°=m∠JML Simplification
6. ∠JML is a right angle. Definition of right angle