Elena wants to prove that a quadrilateral with 4 right angles must have congruent opposite[br]sides. Explain to Elena how she can use the fact that all rectangles are parallelograms in[br]her proof.[br]
IM G Unit 2 Lesson 12 from IM Geometry by Illustrative Mathematics, [url=https://im.kendallhunt.com/HS/students/2/2/1/index.html]https://im.kendallhunt.com/HS/students/2/2/12/index.html[/url]. Licensed under the Creative Commons Attribution 4.0 license, [url=https://creativecommons.org/licenses/by/4.0/]https://creativecommons.org/licenses/by/4.0/[/url].