What does it mean for a pair to be congruent in geometry?

What does it mean for a pair to be congruent in geometry?

• A. They match in size and shape.
• B. They are perpendicular.
• C. They are parallel.
• D. They are complementary.

Answer: (A)

Congruence means two figures have the same size and shape. If you move one figure with rigid motions—sliding, rotating, or flipping—it can be placed exactly over the other, with corresponding sides equal in length and corresponding angles equal in measure. That precise match shows the figures are congruent. The other ideas describe line or angle relationships (perpendicular means a 90-degree intersection, parallel means never meeting, complementary means angles that sum to 90 degrees) rather than the overall equivalence of two figures.

Congruence means two figures have the same size and shape. If you move one figure with rigid motions—sliding, rotating, or flipping—it can be placed exactly over the other, with corresponding sides equal in length and corresponding angles equal in measure. That precise match shows the figures are congruent. The other ideas describe line or angle relationships (perpendicular means a 90-degree intersection, parallel means never meeting, complementary means angles that sum to 90 degrees) rather than the overall equivalence of two figures.