Respuesta :
Answer:
The answer is 1 side must measure 90
Step-by-step explanation:
To make sure that a parallelogram is a rectangle, we need at least one angle measure 90°.
What is a parallelogram?
A quadrilateral with opposing sides parallel is known as a parallelogram (and therefore opposite angles are equal). A rhombus is a quadrilateral with equal sides, whereas a rectangle is a parallelogram whose angles are all right angles.
How are angles of a parallelogram related?
A parallelogram is a flat two-dimensional form with four angles. The inner angles opposite each other are equal. The transversal angles on the same side are supplementary, meaning they sum up to 180 degrees. As a result, the total of a parallelogram's internal angles equals 360 degrees.
How do we solve the given question?
We are asked the minimum number of right angles (90°), for a parallelogram to be a rectangle.
Let the given parallelogram be ABCD. For a parallelogram to be a rectangle, all its angles need to be 90°. Let ∠A = 90°.
∴∠C = ∠A = 90°. (∵ Opposite angles of a parallelogram are equal)
∠A + ∠B = 180°. (∵ Adjacent angles are supplementary, that is, their sum is 180°)
⇒∠B = 180°- ∠A = 180° - 90° = 90°
∴∠D = ∠B = 90°. (∵ Opposite angles of a parallelogram are equal)
∴ All four angles are right angles (90°), given one angle = 90°.
∴ To make sure that a parallelogram is a rectangle, we need at least one angle measure 90°.
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