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ERIC Number: EJ1070873
Record Type: Journal
Publication Date: 2015-Aug
Pages: 8
Abstractor: ERIC
ISSN: ISSN-0025-5769
Shadow Puppets: Exploring a Context for Similarity and Dilations
DeJarnette, Anna F.; Rosado Lausell, Sahid L.; González, Gloriana
Mathematics Teacher, v109 n1 p20-27 Aug 2015
How can geometry teachers design great tasks that allow students to make connections among interrelated concepts and expand their geometric reasoning skills? Many curricular materials provide problems for students to apply a single geometric concept. However, these problems do not always promote reasoning opportunities for students, because students may not look for connections with other geometric ideas or explore alternative solution strategies. For classroom teachers, this detachment raises an important question: What does it take to transform a typical geometry exercise into a great task to promote students' geometric reasoning and sense making? the authors use the term task to refer to a problem as well as students' interpretation of what they should produce and students' use of resources and strategies to achieve that product. A great task begins with a problem, but it also includes how the teacher launches the problem and the work that students do to solve it. In this article, the authors illustrate how they transformed a typical geometry problem into a great task.
National Council of Teachers of Mathematics. 1906 Association Drive, Reston, VA 20191-1502. Tel: 800-235-7566; Tel: 703-620-3702; Fax: 703-476-2970; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: High Schools; Secondary Education
Audience: Teachers
Language: English
Sponsor: National Science Foundation (NSF)
Authoring Institution: N/A
Grant or Contract Numbers: DRL-1253081