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ERIC Number: EJ1092794
Record Type: Journal
Publication Date: 2016-Mar
Pages: 9
Abstractor: ERIC
ISSN: ISSN-1072-0839
Dilations and the Equation of a Line
Yopp, David A.
Mathematics Teaching in the Middle School, v21 n7 p406-414 Mar 2016
Students engage in proportional reasoning when they use covariance and multiple comparisons. Without rich connections to proportional reasoning, students may develop inadequate understandings of linear relationships and the equations that model them. Teachers can improve students' understanding of linear relationships by focusing on realistic situations and directing students' attention toward the dependency of x and y and the covariant relationship expressed in linear equations. In this article, the author presents how to track students' understanding of proportional reasoning by combining transformational geometry, similar-triangle reasoning, and linear relationships.
National Council of Teachers of Mathematics. 1906 Association Drive, Reston, VA 20191. Tel: 800-235-7566; Tel: 703-620-9840; Fax: 703-476-2570; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Grade 8; Junior High Schools; Middle Schools; Elementary Education; Secondary Education; Grade 7
Audience: Teachers
Language: English
Sponsor: National Science Foundation (NSF)
Authoring Institution: N/A
Grant or Contract Numbers: 1317034