Question

If both pairs of opposite angles of a quadrilateral are __________, then the quadrilateral is a parallelogram.

A) supplementary

B) congruent

C) obtuse

D) complementary

Answer 1

B. Congruent

Explanation:

For a shape to be a quadrilateral, opposite sides must be equal, and opposite angles must be equal (congruent).

Answer 2

B) congruent

Explanation:

If both pairs of opposite angles of a quadrilateral are congruent, then the quadrilateral is a parallelogram. This is a converse of the parallelogram opposite angles theorem, which states that the opposite angles of a parallelogram are congruent.

Therefore, the answer is B. congruent

The other answer choices are not correct:

• Supplementary angles are two angles that add up to 180 degrees. While supplementary angles can be found in parallelograms, they are not a defining characteristic of parallelograms.
• Obtuse angles are angles that measure between 90 degrees and 180 degrees. Parallelograms can have obtuse angles, but they can also have acute angles (angles that measure less than 90 degrees) and right angles (angles that measure exactly 90 degrees).
• Complementary angles are two angles that add up to 90 degrees. While complementary angles can be found in parallelograms, they are not a defining characteristic of parallelograms.