Final answer:
In parallelogram KLMN, opposite angles are proved congruent by showing that consecutive angles are supplementary, and then using the Subtraction Property of Equality to deduce that ∠N ≅ ∠L and ∠M ≅ ∠K.
Step-by-step explanation:
To prove that in parallelogram KLMN, the angles ∠N ≅ ∠L and ∠M ≅ ∠K, we follow a series of logical statements based on the properties of parallelograms and congruence relationships.
- Parallelogram KLMN is given.
- The opposite sides of a parallelogram are parallel by definition, so KL ∥∥ NM and KN ∥∥ LM.
- In a parallelogram, consecutive angles are supplementary, so m∠K + m∠N = 180° and m∠L + m∠M = 180°.
- However, opposite angles of a parallelogram are congruent. This means that m∠K + m∠N = m∠K + m∠L and m∠L + m∠M = m∠K + m∠L.
- Using the Subtraction Property of Equality, we deduce that m∠N = m∠L and m∠M = m∠K.
- Therefore, ∠N ≅ ∠L and ∠M ≅ ∠K.