Is it possible to construct a 4-sided figure in which— all the angles are equal to 90° but opposite sides are not equal?
No, it is not possible to construct a 4-sided figure where all angles are 90° but opposite sides are not equal.
Reasoning: In any quadrilateral with all four angles equal to 90°, the opposite sides must be equal in length. When all angles are right angles, the figure must be a rectangle. By definition, a rectangle has opposite sides equal. Any attempt to construct such a figure with unequal opposite sides will result in angles that are not all 90°.
Conclusion: ∴ Such a figure cannot be constructed.
Explanation
The chapter establishes that a rectangle has two properties: R1) Opposite sides are equal, and R2) All angles are 90°. These properties are interconnected. If all angles are 90°, the figure must be a rectangle, which automatically means opposite sides are equal. This is a fundamental geometric principle.
Solution Steps
A quadrilateral with all angles = 90° must be a rectangle.
A rectangle has opposite sides equal by definition.
Therefore, opposite sides must be equal if all angles are 90°.