Given: parallelogram klmn prove: ∠n≅∠l and ∠m≅∠k statement reason parallelogram klmn given kl¯¯¯¯¯∥nm¯¯¯¯¯¯¯ and kn¯¯¯¯¯¯∥lm¯¯¯¯¯¯ m∠k+m∠n=180° m∠l+m∠m=180° m∠k+m∠l=180° same-side interior angles theorem m∠k+m∠n=m∠k+m∠l m∠l+m∠m=m∠k+m∠l m∠n=m∠l m∠m=m∠k ∠n≅∠l and ∠m≅∠k angle congruence postulate substitution property of equalitytransitive property of congruencesubtraction property of equalitydefinition of parallel linesdefinition of parallelogram