consecutive angles in a parallelogram

Check the final answer first, then review the worked steps.

Problem

consecutive angles in a parallelogram

Answer

D. supplementary

Step-by-step solution

  1. Definition of a parallelogram: A parallelogram is a quadrilateral where both pairs of opposite sides are parallel.
  1. Analyze the properties of angles: In a parallelogram, consecutive angles (angles that share a common side) are formed by two parallel lines intersected by a transversal (the side connecting them).
  1. Apply geometric theorems: According to the properties of parallel lines, interior angles on the same side of a transversal are supplementary, meaning their sum is $180^{\circ}$. Therefore, any two consecutive angles in a parallelogram add up to $180^{\circ}$.
  1. Conclusion: Since the sum of the two consecutive angles is $180^{\circ}$, they are defined as supplementary angles.