A. Parallelogram Property 3 In a parallelogram, any two consecutive angles are supplementary. Given: Parallelogram LIFE Prove: angle I and angle F are supplementary angle F and angle E are supplementary angle E and angle L are supplementary angle L and angle I are supplementary a Opposite sides of parallelograms c Opposite angles of parallelog are parallel. congruent. b Same side interior angles of d Parallelogram LIFE. parallel segments cut by a and angle E are supplementary, angle E ar transversal are supplementary. e angle F supplementary, angle L and angle 1 are supps tary to the other also.