This is a study of secondary mathematics teachers' use of a digitally enhanced educational technology called Interactive Diagrams (IDs). This study is concerned with the ways in which mathematics teachers use IDs as they plan and enact classroom activities involving this technology, as well as the factors that affect their ID use. Qualitative research methods were used to conduct this exploratory study focused on the practice of three teachers within a large urban school district. Using Remillard's (2005) conceptualization of teacher-curriculum interactions allowed participants' instructional practices to be situated within an environment affected by contextual, curricular, teacher, and student factors. Mediating factors within each of these areas were identified for the study participants using inductive coding techniques. Teachers' intended and enacted uses of selected IDs were also analyzed using this research methodology. The results of this analysis are described, as well as implications for future practice and research. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]