Given: e ll f and g is transversal Prove: ∠1 ≅ ∠8


Given that e II f and g is a transversal, we know that ∠4 ≅ ∠5 by the alternate interior angles theorem. We also know that ∠1 ≅ ∠4 and ∠5 ≅ ∠8 by the _____. Therefor, ∠1 ≅ ∠8 by the substitution property.


A. Corresponding angles theorem


B. Alternate interior angles theorem


C. Vertical angles theorem


D. Alternate exterior angles theorem