1. The problem asks about the properties of angles and diagonals in a rectangle. 2. In any rectangle, all angles are right angles, meaning each angle measures 90 degrees. 3. Opposite angles in a rectangle are therefore equal and each pair sums to 180 degrees, making them supplementary. 4. The diagonals of a rectangle are congruent, meaning they have the same length. 5. To summarize: - Opposite angles are supplementary. - Diagonals are congruent. This is a fundamental property of rectangles in geometry.