
Philip P. answered 01/17/23
Affordable, Experienced, and Patient Geometry Tutor
Without the diagram it's a little challenging but I was able to reason out that KL is a transversal cutting across parallel lines AB and EF. Thus angles BKL and KLF are same-side interior angles and are supplementary. Angles BKL and AKL are a linear pair so they are also supplementary. You can then equate m∠KLF + m∠BKL to m∠BKL + m∠AKL by the transitive property. So the answer is:
- Same-Side Interior Angles Theorem; 2. Transitive Property