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ERIC Number: EJ1110637
Record Type: Journal
Publication Date: 2016-Aug
Pages: 4
Abstractor: As Provided
ISSN: ISSN-1072-0839
Estimating Earth's Circumference with an App
Cooper, Linda; Dennis, Emily
Mathematics Teaching in the Middle School, v22 n1 p47-50 Aug 2016
More than 2,200 years ago, Eratosthenes, who was a Greek astronomer, geographer, and mathematician, used a simple proportion involving the distance between two ancient cities and measures of shadows cast in those cities during a summer solstice to estimate the circumference of Earth (Nicastro 2008, 25-28). Today, middle school students can use similar proportional reasoning with physical measurements easily collected by a smart phone and trundle wheel to duplicate the feat of estimating Earth's circumference. Within this hands-on discovery activity, students explore the seventh-grade Common Core standard to "analyze proportional relationships and use them to solve real-world and mathematical problems" (CCSSI 2010, p. 47) using popular technology and integrating concepts of latitude and longitude.
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: Middle Schools; Secondary Education; Junior High Schools
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A